McKinnon started in the 2011/12 season in the Nor-Am Cup. She won five competitions and took first place in the Aerials discipline. In the World Cup she made her debut on January 20, 2012 in Lake Placid and achieved 15th place. Two months later she won the bronze medal at the Junior World Championships 2012 in Chiesa in Valmalenco . At the 2013 World Championships in Voss , she came in 14th place.
At the beginning of the 2014/15 season McKinnon achieved their first World Cup èodest placements in Beijing with second and third place. As the season progressed, she finished second in Deer Valley and Minsk and third in Moscow . She won the silver medal at the 2015 World Championships at Kreischberg . She finished the season in third place in the overall World Cup, while she won the Aerials discipline ranking (without having won a jumping).
In the following season 2015/16 McKinnon came in six World Cup competitions four times in the top ten, including 3rd place in Beijing, and at the end of the season he achieved sixth place in the Aerials discipline. In the 2016/17 season she came ninth in the Aerials discipline. She finished second in Deer Valley. At the highlight of the season, the 2017 World Championships in Sierra Nevada , she finished fourth. Her first World Cup victory was on January 6, 2018 in Moscow.