Early career

Pineault began learning to skate in 2003.^[1] Coached by Stéphane Yvars and Françoise Parisé in Boucherville, she won silver in the novice ladies' category at the 2015 Canadian Championships and silver in the junior ranks at the 2016 Canadian Championships.^[3]

In September 2016, Pineault appeared at the ISU Junior Grand Prix in the Czech Republic, finishing tenth. Competing on the senior level, she placed seventh at the 2017 Canadian Championships.

2017–2018 season

Making her international senior debut, Pineault placed sixth at the 2017 CS U.S. Classic in September. In January, she finished eighth at the 2018 Canadian Championships and was selected to compete at the 2018 Four Continents Championships in Taipei; she placed fourteenth in the short program, twelfth in the free skate, and thirteenth overall in Taiwan.

2018–2019 season

Pineault finished sixth at the 2018 CS Autumn Classic International. In October, she was invited to compete at her first Grand Prix event, the 2018 Skate Canada International, following the withdrawals of Gabrielle Daleman and Larkyn Austman.^[4] Pineault had to withdraw from the 2019 Canadian Championships after spraining her ankle in two places in the practice sessions.^[5]

2019–2020 season

Pineault placed seventh at the 2019 CS U.S. Classic at the beginning of the season. Competing at Skate Canada International for the second consecutive season, she was eleventh of twelve skaters.^[6]

Pineault placed first in the short program at the 2020 Canadian Championships despite having an underrotation called on the second part of her jump combination.^[5] She had more difficulty in the free skate, landing only two triple jumps cleanly, and dropped to fourth place overall.^[7] Because national champion Emily Bausback lacked the senior technical minimum for the short program to be assigned to the 2020 World Championships, Skate Canada deferred making a decision about assigning its two berths there until after the 2020 Four Continents Championships in Seoul. As national bronze medalist Madeline Schizas was ineligible for international senior competitions, Pineault was assigned to Four Continents along with Bausback and silver medalist Alison Schumacher.^[8]

At the Four Continents, Pineault placed tenth with personal best results in both the free skate and total score.^[9] She was the highest-ranking Canadian woman at the event, besting Schumacher (in fourteenth place) by almost 23 points.^[10] After Pineault's result at Four Continents, she was assigned to compete at the 2020 World Championships,^[11] The championships were subsequently cancelled as a result of the coronavirus pandemic.^[12]

2020–2021 season

Due to the COVID-19 pandemic, Grand Prix assignments were made based on training location, and Pineault was assigned to 2020 Skate Canada International. After the event was cancelled, she announced that due to ongoing uncertainties surrounding the season, she would not compete the rest of the season. Pineault instead took the time to follow doctors' recommendations to "tune some physiological aspects" and recover from injuries.^[13]

2021–2022 season

Returning to competition, Pineault was fifth at the 2021 Skate Canada Challenge and then finished seventh at the 2022 Canadian Championships.^[14]