In 2017, Maanum left Lyn to join Stabæk. She had been involved in all of their matches, before it was announced that she had completed a transfer toDamallsvenskan clubLinköping after only half a season with Stabæk.[3]
At the age of 18, Maanum joinedSwedish side Linköping. She would go on to win the2017 Damallsvenskan title in her debut season.[4] Maanum quickly became a key player, and in the 2020–21 season, was named as club captain at the age of 21. She marked her last appearance for the club with a goal in a 4–1 victory overÖrebro.[5] In May 2021, local newspaperCorren placed Maanum in 14th place when naming the 30 best players to have played for Linköping.[6]
On 27 July 2021,Women's Super League giantsArsenal confirmed the signing of Maanum.[7][8] She quickly established herself as an exciting player. On 5 October, Maanum scored her first goal for Arsenal in aChampions League match againstBarcelona.[9] On 12 December, Maanum came off the bench and netted a brace in a 4–0 win overLeicester City.[10] Despite a blistering start, her playing time decreased in the second half of the season.[11] She was nevertheless nominated for Young Player of the Year for the 2021–22 Women's Super League season.[12]
On 19 October 2022, Maanum was handed her first start of the season in Arsenal'sChampions League away match against reigning championsLyon, and got on the scoresheet in an emphatic 5–1 win for the Gunners.[13] Four days later on 23 October, Maanum scored her first league goal of the season in a 2–0 away victory againstLiverpool.[14] She was later voted as Arsenal's Player of the Month for October 2022.[15] On 21 December, she scored ahat-trick and provided an assist in a 9–1 group stage win overZürich in the Champions League, earning thePlayer of the Match award.[16] On 26 January 2023, Maanum scored twice in a 3–0 win overAston Villa in theConti Cup. She was then voted Arsenal's Player of the Month for January 2023.[17] Maanum played the full 90 minutes in Arsenal's 3–1 Conti Cup final triumph over London rivalsChelsea on 5 March.[18] On 25 March, Maanum scored Arsenal's fifth goal in a 5–1North London Derby win overTottenham Hotspur.[19] Three days later on 29 March, Maanum scored a delightful goal from outside the box, helping Arsenal to a 2–0 (2–1 on agg.) second-leg victory overBayern Munich, and earning Arsenal a spot in the Champions League semi-finals.[20] This goal was later voted by fans as theUEFA Women's Champions League Goal of the Season.[21] On 2 April, Maanum scored the crucial equaliser in Arsenal's home match againstManchester City, which Arsenal went on to win 2–1.[22] Maanum finished the season with a tally of 16 goals and 5 assists in all competitions.[23] She won the Arsenal Women Supporters Club Player of the Season award,[24] and was nominated for both Arsenal Player of the Season[25] and theWomen's Super League Player of the Season.[26]
On 1 June 2023, after a stellar second campaign, it was announced that Maanum had signed a new contract with the club.[27]
On 19 November 2023, Maanum scored her first league goal of the season in a 3–0 away win againstBrighton.[28] In December 2023, she won theFootball Supporters' Association Player of the Year award.[29]
On 31 March 2024, Maanum collapsed off the ball in the2023-2024 FA Women's League Cup final.[30] She was given oxygen at the scene after being down for around 9 minutes, before being stretchered off. Arsenal later reported that she was 'conscious, talking and stable'.[31] On 4 April, Arsenal confirmed that she had undergone extensive testing and that there were 'no obvious cardiac causes found'. Maanum was fitted with a monitoring device to record her heart function and was cleared to undergo a progressive return to training protocol for a one-week period, before a decision would be made as to when she would return to play.[32]
On 22 September 2024, Maanum scored the early opener in Arsenal's 2–2 draw against Manchester City atEmirates Stadium in their first match of the2024–25 Women's Super League season.[33] On 26 September, she came off the bench to score Arsenal's fourth goal in a 4–0 (4–1 on agg.) victory againstBK Häcken, which ensured that Arsenal progressed to the Champions League group stages.[34]
In November 2024, Maanum won the Emirates goal of the month, for her spectacular goal againstBrighton & Hove Albion.[35]
At the age of 17, Maanum was selected to represent the seniorNorwegian national team at the2017 Euros.[36][37][38] At that point, she had only played 10 matches in Norway's top division. Maanum made her debut on 11 July 2017, where she started in a match againstFrance. Less than a week later, Maanum was handed another start in Norway's opening match at theEuros, which was against theNetherlands, the country hosting the tournament.[39]
On 27 October 2020, Maanum scored the match-winning goal againstWales, which earned Norway qualification for the2022 Euros.[40]
She was called up to Norway's squad for both the2019 World Cup and the 2022 Euros.[41][42]
On 15 November 2022, Maanum scored an equaliser in a friendly match againstEngland.[43]
^Fotballforbund, Norges."Her er Norges VM-tropp".www.fotball.no (in Norwegian).Archived from the original on 13 January 2024. Retrieved30 January 2023.
^AS, TV 2 (6 September 2023)."- Håper det blir bra".TV 2 (in Norwegian Bokmål).Archived from the original on 1 April 2024. Retrieved1 April 2024.{{cite web}}: CS1 maint: numeric names: authors list (link)