Delaney began his career at Copenhagen, making 249 total appearances and scoring 24 goals, while winning the Danish Superliga five times and theDanish Cup on four occasions. He then played in Germany forWerder Bremen andBorussia Dortmund, making 107 totalBundesliga appearances, before a move toSevilla in 2021. Following loan stints atTSG Hoffenheim andAnderlecht, Delaney returned to Copenhagen in 2024.
Delaney made his debut for Copenhagen in an unofficial friendly in August 2008. After playing the first half of the2008–09 season in the KB youth team, he was a part of the FCK squad in theDanish Cup that campaign. He made his official debut in the first leg of the semi-finals againstNordvest FC in April, where he substitutedHjalte Nørregaard in the middle of second half.[3] In the return leg two weeks later Delaney was among the starting eleven playing the first 60 minutes before he was substituted withŞaban Özdoğan.
In the summer break 2009, he was promoted to the first team squad together withŞaban Özdoğan. He scored on his continental debut on 22 July 2009, playing the full second leg in Copenhagen'sChampions League second qualifying round victory overFK Mogren.[4][5] His firstSuperliga match was on 9 August 2009 againstSønderjyskE replacingAtiba Hutchinson near the end of the match.[6] On 29 December 2011, signed a contract extension keeping him at Copenhagen until the end of 2014.[3] At the time, Delaney had the distinction of being the longest serving current player at the club, despite being only 20.[3]
On 6 July 2013, Delaney extended his contract with the club to 2015. At the same time, he got jersey number 8.[7] In the following season, he became a regular starter in his favorite position, includingUEFA Champions League matches againstJuventus,Real Madrid andGalatasaray. On 23 January 2014, he again extended his contract, until 2017.[6] At the same time, he was officially named vice-captain of the team.[6] Half a year later, Delaney was promoted to club captain.
On 14 May 2015 he was named Man of the Match as his side won theDanish Cup final 3–2 after extra-time against fellow Superliga sideFC Vestsjælland.[8][9]
On 27 September 2016, Delaney contributed to a comfortable 4–0 victory for his side with a left-footed half-volley from 30 yards against Belgian sideClub Brugge KV[10] in theUEFA Champions League.[11]The goal came third in the vote for goal of the season in the UEFA Champions League.[12]
On 17 August 2016,Werder Bremen announced Delaney would be joining the club in January 2017.[13][14] On 18 February 2017, he scored his first goal for the club, a free kick, in Werder Bremen's 2–0 win away toMainz 05 before being stretchered off the pitch with a suspected concussion. It was the club's first win of the new year following four straight defeats.[15]
On 1 April 2017, Delaney scored ahat-trick, the first of his career, in Werder Bremen's 5–2 win away againstSC Freiburg.[16]
On 7 June 2018, Delaney signed forBorussia Dortmund on a four-year contract. The transfer fee paid to Werder Bremen was reported as €20 million.[17][18]
He made his debut for the club on 27 August 2023 in a 2-1 victory againstCharleroi.
He scored his first goal for the Mauves on 1 december 2023, in a 3-1 away win againstKVC Westerlo.
With Anderlecht, Delaney was inconsistent, mainly due to injuries, which limited his playing time at the Belgian giants, eventually leading toAnderlecht not triggering the buy option for Delaney.[23] He made a total of 25 appearances for the club.
Delaney made his debut for the Denmark under-18 team in October 2008, and went on to play three matches in total. He played 11 games for theDenmark U-19 team. On 11 August 2010, he made his debut for theDenmark U-21 team in a friendly against theItaly U-21 team.
Delaney scored his first international goal on 1 September 2017 to open a 4–0 home win over Poland in2018 FIFA World Cupqualification.[27] Three days later, he scored a hat-trick as the team came from behind to win 4–1 away toArmenia.[28]
In June 2018, he was named in Denmark's squad for the World Cup in Russia.[29] He was also named in the 26-man squad forUEFA Euro 2020.[30] He scored the first goal in the 2–1 quarter-final game against theCzech Republic.[31]
On 25 August 2024, Delaney announced his retirement from international football. He scored eight goals in 81 international appearances.[32]
Delaney was born in Denmark and spent his youth there. His father was also born in Denmark but has American citizenship due to his own father (Thomas Delaney's paternal grandfather) being born in the United States.[33] Delaney also has Irish roots through his paternal great-grandfather who moved from Ireland to the United States in the 19th century during theGreat Famine.[34]
Delaney married Michelle Lindemann Jensen on 27 December 2020. Michelle is the daughter of formerBrøndby coachHenrik Jensen and the sister of former national team playerMike Jensen.[38] Delaney and Michelle met while studying atNiels Brock Copenhagen Business College. They have a daughter, Billie, born in February 2021.[39]