Rukajärvi has been participating in the Ticket to Ride World Snowboard Tour competitions since 2007 . She achieved her first international success at the Snowboard Junior World Championships 2008 in Valmalenco . There she won bronze in Big Air . In April 2008 she became Finnish champion in slopestyle. She repeated this a year later and also won the half-pipe competition. In the 2009/10 season she won slopestyle at the Pleasure Jam in Schladming , the Roxy Chicken Jam Europe in Saalbach , the Burton European Open 2010 in Laax , the Burton Canadian Open in Calgary and the Oakley Girls Sessions in Ruka . She finished the season on the World Snowboard Tour in first place overall. In August 2010 she won gold in Big Air and in Slopestyle at the Snowboard Junior World Championships . The following season she won the 2010 Horsefeathers Pleasure Jam, the Burton US Open and the 2011 Winter X Games in the slopestyle competition. At the 2011 World Championships in La Molina , she won the gold medal in the first-ever slopestyle competition. In January 2012 she won silver in slopestyle at the Winter X Games 2012 . In 2012 she became Finnish champion in slopestyle. In the 2012/13 season she won the Burton High Fives 2012 in New Zealand and the FIS World Cup in March 2013 in Špindlerův Mlýn and reached twelfth place in Cardrona and fifth in Copper Mountain . She finished the season on the World Snowboard Tour in second place overall and second place in the FIS Slopestyle overall ranking.
The following season, Rukajärvi won second place in slopestyle at the Burton High Fives in Cardrona and at the Winter Dew Tour in Breckenridge . At the season highlight of the 2014 Winter Olympics in Sochi , Russia , Rukajärvi won silver in the first-ever slopestyle competition on February 9th. After finishing second in slopestyle at the Winter Dew Tour in Breckenridge at the beginning of the 2014/15 season, she finished sixth at the 2015 Winter X Games in January 2015 and third at the Burton European Open in Laax. The following month, she was also third in slopestyle at the US Snowboarding Grand Prix in Mammoth . At the 2016 Snowboard World Championships in Yabuli , she won the silver medal in both slopestyle and big air. In April 2016 she became Finnish champion in Slopestyle and Big Air. After finishing second in Big Air at the US Snowboarding Grand Prix and World Cup in Copper Mountain at the beginning of the 2016/17 season, she won the Slopestyle World Cup on the Seiser Alm , at the Laax Open and at the same time the World Cup in Laax and at the Big Air event Air & Style in Innsbruck . In March 2017 she was fourth in the Slopestyle at the X-Games Norway 2017 in Hafjell and won the silver medal in Big Air at the Snowboard World Championships 2017 in Sierra Nevada . She finished the season in fifth place in the Freestyle World Cup and in fourth Rank in the Slopestyle World Cup. After finishing third at the Air & Style in Beijing and third in slopestyle at the Winter Dew Tour in Breckenridge at the beginning of the 2017/18 season, she won the bronze medal in slopestyle and the X Games at the 2018 Winter X Games in Aspen Norway 2018 in Fornebu the bronze medal in Big Air. At the Olympic Winter Games 2018 in Pyeongchang she won the bronze medal in slopestyle on February 12th. In the Big Air competition, she came 16th there.
After finishing third on the Winter Dew Tour in Breckenridge in slopestyle at the beginning of the 2018/19 season, Rukajärvi won the bronze medal in slopestyle at the Winter X-Games 2019 . In addition, she was there fourth in Big Air and at the following World Championships in Park City tenth in Slopestyle. In April 2019 she won the Finnish championships in Slopestyle and Big Air in Ruka . In the 2019/20 season she won her fourth World Cup in Big Air in Cardrona and thus achieved sixth place in the Big Air World Cup. She also finished eighth at the Winter X Games 2020 and fourth in slopestyle at the Burton US Open and seventh in both slopestyle and big air at the X-Games Norway 2020 in Hafjell .