Majasaari started her career at NiceFutis in Pori. She played her first Naisten Liga match with NiceFutis at the age of 14 in the Autumn of 2014. From 2016 to 2018, Majasaari played in TPS, which won the 2016 Naisten Liga silver.[2] For the 2019 season, Majasaari moved to FC Honka, which placed second in the Naisten Liga during that season.[3]
In December 2019, Majasaari signed a contract with AIK, who played in the Sweden second tier division Elitettan.[4] In her first Swedish season, Majasaari played full minutes in all AIK matches and had 13 clean sheets. She was chosen as the best goalkeeper of the Elitettan season.[5] The season ended with a victory for AIK and a promotion to Damallsvenskan.[6] In November 2020, she signed a three-year extension with AIK.[7] She played her first league match in Damallsvenskan on 17 April 2021.[8]
On 5 January 2023, Majasaari was announced at IK Uppsala.[9] On 14 May 2023, she kept a clean sheet and saved a penalty against IFK Kalmar.[10]
On 31 August 2024, Majasaari was announced at Crystal Palace.[13]
International career
Majasaari has represented Finland in the U-16, U-17, U-18 and U-19 teams and in the women's U-23 national team. She played her first international match at the age of 14 on the U-16 national team against Iceland in the summer of 2014.[14] Majasaari participated in the Euro 2022 qualifier against Scotland for the first time in October 2020 with the Finnish national team, in which she was called to replace the injured Paula Myllyoja.[15]