Born inFăgăraș,Brașov County, Dan earned international acclaim in his youth as a mathematician, securing gold medals and perfect scores at the 1987 and 1988International Mathematical Olympiads. He began studying mathematics at theUniversity of Bucharest and then moved to France, where he obtained amaster's degree fromÉcole normale supérieure and aPhD fromParis 13 University. After returning to Romania, Dan founded Școala Normală Superioară București, an institution aimed at guiding the most talented Romanian students towards scientific research, and became a civic activist.
In 2015, Dan founded theSave Bucharest Union (USB), focusing onanti-corruption and heritage preservation. One year later, he co-founded theSave Romania Union (USR), but resigned from the party in 2017 over itsprogressive shift, preferring a morecentrist approach. Dan served in theChamber of Deputies from 2016, before being electedBucharest's secondindependent mayor in 2020[1] and winning re-election in 2024. As mayor, he focused on public infrastructure and transparency, although he received criticism over construction delays.
In 1992, he moved to France to continue studying mathematics; he attended theÉcole Normale Supérieure, one of the most prestigious Frenchgrandes écoles, where he earned a master's degree. In 1998 Dan completed a PhD in mathematics atParis 13 University, with thesis "Courants de Green et prolongement méromorphe" written under the direction ofChristophe Soulé andDaniel Barsky [de].[11][12] He returned to Bucharest that year, giving as reasons the cultural differences and the desire to change Romania.[13]
In 1998, Dan foundedAsociația "Tinerii pentru Acțiune Civică" ("Young People for Civic Action" Association), for which he wanted to gather a thousand young people who wanted to change Romania, which was his stated goal for returning to the country.[13] Despite failing in its goals, the association did organise two forums for young people who studied abroad, in 2000 and 2002, to which a few hundred people participated. As result of these forums, the "Ad Astra" Association of Romanian researchers was created in 2000.[13]
Dan founded theAsociația "Salvați Bucureștiul" ("Save Bucharest" Association) in 2006 as a reaction to the demolition of architectural heritage houses and the building of high-rise buildings in protected Bucharest neighborhoods, as well as the diminishing number ofgreen space areas in Bucharest.[13]
In March 2008, the association published the "Bucharest, an urbanistic disaster" Report, which discussed Bucharest's problems and ways to overcome them. In the same year, during the elections, together with otherNGOs, the association drafted aPact for Bucharest, which was signed by all the candidates for mayor of Bucharest.[13] OnApril Fools' Day in 2012, Dan published a list of 100 electoral promises made by elected mayor of BucharestSorin Oprescu which were not kept, including the "Pact for Bucharest".[10][15]
The association was involved in many trials, winning 23 trials against the local authorities of Bucharest. Among them are the cancellation of a project which would have built awater park on 7 hectares ofTineretului Park,[10] saving from demolition a number of heritage buildings onȘoseaua Kiseleff no. 45, and the cancelation of a project which would have built a glass building on top of Palatul Știrbei onCalea Victoriei.
The association was also able to push for some changes in 2009 to theurban planning law.[10]
Dan on a bicycle during his electoral campaign for Mayor of Bucharest in 2012
Dan announced his candidacy forMayor of Bucharest in November 2011 at a café on Arthur Verona Street, with just a few guests, includingTheodor Paleologu, a historian and Member of Parliament.[14]
Volunteers in Dan's campaign carrying the signatures to the Electoral Bureau
For gathering the 36,000 signatures needed for his candidacy, having the backing of no party, he relied on a network of volunteers organised onFacebook. On 22 April 15 bands and musicians performed pro-bono atArenele Romane [ro] for Dan's campaign in order to help him gather the signatures.[16] During the 12-hour-long concert, volunteers gathered 4,000 signatures.[17]
Among his proposed projects are the creation of alight rail infrastructure over the existing rail lines in Bucharest, creating an infrastructure forprioritisingpublic transport over other traffic in intersections, consolidating buildings that are likely to be affected by earthquakes, protecting the urban green space and clearing illegal buildings from parks.[14]
Dan argues that it is important to incentivise young people to stay in the city, by making it a regional hub in IT,creative industries andhigher education, and attracting investors and skilled people from across the region.[18][19]
He received support fromAndrei Pleșu, who argued that Dan was the only one of the candidates who was interested in the architecture of Bucharest and did not support any utopian initiatives.[20] He also received support from political scientist and Member of the European ParliamentCristian Preda.[21]
Dan gained the support of some journalists who wrote about him inop-eds from several newspapers: Andrei Crăciun ofAdevărul saw in him "aDon Quijote untouched by the vulgar lard of undeserved riches" and "a person who works against the system".[22] Florin Negruțiu, the editor-in-chief ofGândul thought he was an "atypical candidate" for Bucharest, the model candidate of the intellectuals; nevertheless, the journalist did not see any chances that Dan would become mayor, because he was "too serious" a candidate, and unlikely to appeal to the masses.[23]Neculai Constantin Munteanu fromRadio Free Europe wrote that he supported Dan for his unselfish way of caring about Bucharest and that his opponents were "comedians", from whom one could "admire the imposture, ludicrousness, and incompetence".[24]
Having registeredSave Bucharest Union (USB) as a political party in 2015, Dan ran again forMayor of Bucharest in 2016.[25] This time,the elections were held in a single round. He gained 30.52% of the total votes, losing to the social-democrat candidate,Gabriela Firea, who gained 42.97% of the total votes.[26]
In the election, Dan managed to attract the young electorate, with over half of his voters being under the age of 40.[27] Some of USB's candidates forsector mayor have also performed well in their respective races, proving USB's viability as a future political force.[28]
Wanting to capitalise on the momentum that saw him gain a third of the votes in the local elections, Dan announced shortly after the 2016 local election that the Save Bucharest Union would change its name toSave Romania Union (USR), shifting its focus to a national stage. He also announced plans for the new party to enterthe parliamentary elections of that year.[29][30]
With Dan at the top of the candidate list, USR gained 8.92% of the vote in theSenate race and 8.87% in theChamber of Deputies, which made them the third largest party in Romania.[31][32] The result also meant that Dan became a member of the Chamber of Deputies.
In 2017, anti-same-sex NGOCoaliția pentru Familie managed to raise the necessary number of signatures to organise a referendum that would change the part of theRomanian Constitution dealing with marriage, with the hope of redefining it as "between a man and a woman".[33] This created a rift within USR, between the progressive wing, who wanted USR to become the only parliamentary party to oppose the initiative, and Dan, who believed USR should not get involved in the debate and that the party should remain open for both progressives and conservatives.[34][35] An internal referendum within the party followed, in which 52.7% of members voted to position the party against the Constitutional initiative, which led Dan to resign from the party on 1 June 2017.[36][37] As explanation for his opposition to the National Council vote he cited religious matters, the dangers of deviating from the main party issue offighting against corruption and his refusal to belong to a party that defines itself as a party of civil liberties.[38]
After his resignation from USR, Dan continued to serve as a member of the Chamber of Deputies as an independent.
Due to a quirk in the Romanian electoral law, USR required his signature when they attempted to legally registertheir alliance with theFreedom, Unity and Solidarity Party (PLUS). In order to help his former party, in March 2019 Dan briefly rejoined USR as a common member, gave the necessary signature and then resigned for a second time.[39][40]
In May 2019, he announced his plans to once again run for Mayor of Bucharest, as an independent. Dan mentioned that while he hoped that his candidacy would be supported by the rest of the opposition parties, he would not run against a different common candidate, unwilling to split the vote of the opposition.[40]
He was ultimately supported by both USR and theNational Liberal Party (PNL). With 95% of votes counted, partial results suggested that he won the mayoral election with 42.8% of votes. Shortly afterwards exit polls showed him winning the race, he announced victory.[41] On 5 October 2020 the Central Electoral Bureau confirmed his status as the new Mayor of Bucharest, winning the elections with a plurality of 42.81% againstGabriela Firea (37.97%), the former Mayor.[1]
The elections were held on 9 June 2024 together with theEuropean Parliament elections in Romania, a controversial move done by the CNR earlier that year. Thought to be a close race up until the last moment, the exit polls showed the result was overwhelmingly in favour of Dan, winning with 45% of the total vote, who declared himself the winner of the race. After the vote count, Dan was the clear winner of the elections with approximately 48% of the total votes, more than double the votes given to the same runner-up from 2020,Gabriela Firea, who placed second with 22%, followed by thenSector 5 Mayor,Cristian Popescu Piedone (16%) and PNL candidate and president for the Bucharest branch of the party,Sebastian Burduja (7.6%).[42]
During his victory speech, Dan declared his intention to organise two referendums for Bucharest, one for centralising more power to the General Mayor of Bucharest regarding building authorisations, a very consistent theme during his campaign, and another for allocating more financial funds to the General Mayor rather than to the Sector mayors.[43] Both were planned to take place on the same day as theparliamentary elections, in order to "reduce organisational costs for separate elections", according to Dan.
On 14 October 2024,[44] around midnight,Sector 4 mayorDaniel Băluță (PSD) – with permission from Sector 3 mayorRobert Negoiță – sent multiple construction workers and Sector 4 local police agents to Unirii Park in order to start proceedings for the Square's foundation's consolidation. The Piața Unirii is shared between Sector 3 and Sector 4.
In the morning, Dan went to the square together with his staff, telling the workers present to halt the procedure on the basis of its illegality due to a lack of permits. Allegedly,Metrorex and Apa Nova (Bucharest's water and sewage administration institution) had yet to give their approval for the consolidation work.
A conflict erupted between the Sector 4 local police agents (including its director,Cristian Pîslă, subsequently suspected of corruption[45]) and Dan and his staff. Eventually, the Bucharest mayor returned with additional documents attesting to the fact that the City Hall of Bucharest was the legal owner of Unirii Square and the sector City Halls had no right to start consolidation proceedings on their own.[46] During the scuffles, local police agents were observed to be especially violent, which the wide public of Bucharest viewed as proof of the agents being members of the Sector 4Clanul Sportivilor, an organisation of theRomanian mafia operating mainly in the southern part of Bucharest who were long suspected to work with Daniel Băluță himself.[47]
The Romanian prime minister at that time,Marcel Ciolacu, intervened in the matter prompting mayor Băluță to concede; Nicușor Dan launched an investigation into the proceedings. He once again stressed the importance on the referendum held on 9 June 2024 for centralising more power to the Bucharest mayor.
After the Piața Unirii incident, Dan was viewed even more favourably[48] by the general populace of Bucharest, being called a bulwark against the widespread corruption of the country and the only one to effectively stand against the PSD-PNL coalition. This led to speculation of a possible presidential candidature in the next elections. On 16 December he announced his candidacy for the2025 Romanian presidential election,[49] after the annulment of the2024 elections due toRussian meddling in favour of winner of the first roundCălin Georgescu.[50][51][52]
His announcement came as a surprise to many, as he had previously expressed his intention to serve at least one more term as Mayor of Bucharest before the elections, stating that he "would need at least 2-3 terms to make everything right in Bucharest."[53][54] This change of plans also led to a falling out with Elena Lasconi, a former supporter of Dan, who came second in the annulled 2024 elections' first round. It is widely believed that Lasconi and Dan appealed to similar voter demographics, with both targeting liberal, progressive, moderate, pro-European, and anti-PSD/anti-PNL camps. As a result, their simultaneous candidacies may have divided this voter base.[55] TheConstitutional Court validated his candidacy on 16 March along with those ofGeorge Simion andVictor Ponta.[55] On 22 March, a random draw placed Dan at thebottom of the candidate list on the ballot.[56]
Dan came second in the first round of voting on 4 May with 20.99% of the vote. On 18 May, he facedGeorge Simion in a runoff, winning the presidency with 53.6% of the vote.[4]
Dan wasinaugurated as president on 26 May 2025. In his inaugural address, he pledged to deal with Romania’s economic problems while acknowledging that "the Romanian state is spending more than it can afford”. He also pledged to become a president “open to the voice of society.”[57]
During the first weeks of his tenure, Dan was exclusively focused on the formation of the new government. Negotiations were noted to have been a lot longer than in previous years, something that was both praised and criticised by both Romanians and his peers.[59][60][61] Throughout those respective weeks, the newly elected president's image was that of an active and communicative one, oftentimes being greeted by reporters and asked questions in the early morning, right at the gate of the house he and his family were tenants of. Another aspect that painted him in a positive light to the public was that he preffered to take his daughter to school on foot from his house, only accompanyied by aSPP agent. This was a point of friction between him and the protection service due to complications arising in the security procedures regarding the president.[62]
Internationally, Dan's presidency brought some stability in the European Union and NATO, especially concerning their Eastern border. Many analysts opined that Klaus Iohannis' inactivity and corruption scandals sidelined the state in the last months of his presidency, as well as the internal crisis that was caused by the annulment of the2024 elections, election marred by suspicions of Russian interference;[63][64] as such, Romania's internal and international situation was ambiguous and the country was not invited to a security summit in Paris in February 2025.[65]
His election also marked a steady increase in appreciation of the Romanian currency against the Euro after weeks of increases due to market uncertainty in late Spring of 2025, together with a decrease in investment risk for foreign firms.[66][67][68]
He has signed into law substantial legislation since taking office, concerning health system reform,[69] removing housing subsidies for senators and deputies,[70] foreign official corruption,[71] fiscal and budgetary reforms agreed upon by the government in the context of economic rebound[72] and environmental and agricultural regulation.[73]
Dan has consistently advocatedpro-Western views, emphasising Romania's integration into theEuropean Union andNATO as cornerstones of national security and economic progress.
In his 2025 presidential campaign, Dan positioned himself as a staunch defender of Western democratic values; he supported NATO's presence in Romania, particularly amid theRussian invasion of Ukraine, contrasting sharply with George Simion'snationalism andEuroscepticism.[74] Dan is anUkrainophile and advocates for stronger Romanian support to Ukraine.[75][76][77]
In 2000, Dan published an article in the magazineDilema in which he stated his rejection of "homosexual behaviourin public spaces in Romania," describing it as "an attack againsttraditional values" and "legitimatecollective identity". The statements resurfaced after his political career took off, particularly during his much-publicised departure from USR. Dan distanced himself from his previous statements on several occasions, claiming that he is nothomophobic and that his opinion on the matter has changed in the following years.[79][80]
In 2024, Dan expressed support forsame-sex civil partnerships. However, he also believed that it was not the correct time to have a debate. In the same interview, he did not take a stance onsame-sex marriage, and said that “[it] is a debate that society must have.”[81]
In May 2024, ahead of local elections, a purportedSecuritate document from July 1988 emerged, detailing Dan's collaboration with the secret police of theCeaușescu regime. The document contained information provided by Dan about his high school peers who participated in the International Mathematical Olympiads of 1987 and 1988.
Dan denied its authenticity, claiming he had minimal contact with authorities of the time. PSD leader and Prime MinisterMarcel Ciolacu questioned the document's credibility, noting its unusually polished composition. The National Council for the Study of the Securitate Archives (CNSAS) deemed it a forgery, citing incorrect dates, atypical expressions, and a writing style inconsistent with the typewriters used by the Securitate, including the absence of diacritics typical in genuine documents of the era[ambiguous].[82]
^Dan, Nicușor (1998).Courants de Green et prolongement méromorphe [Green currents and meromorphic continuation] (Thesis) (in French). Paris:Université Sorbonne Paris Nord.OCLC708496745.