Gilles/Poirier began the season at the 2019 Autumn Classic, winning by over eighteen points over silver medalists Lilah Fear / Lewis Gibson. For their first Grand Prix assignment, they competed at the 2019 Skate Canada International in Kelowna. They placed second in the rhythm dance, 0.63 points behind defending champions Hubbell/Donohue. They won the free dance and took the gold medal overall by 2.70 points over Hubbell/Donohue, Gilles/Poirier's first Grand Prix gold medal, with Gilles saying they had "worked really hard for this moment." For their second event, the 2019 Rostelecom Cup, they placed second in the free dance behind reigning World silver medalists Sinitsina/Katsalapov. Second in the free dance as well, they won the silver medal and qualified to the Grand Prix Final for the first time in five years. Poirier remarked that they had "had a lot of ups and downs" in the years since, and at times had doubted whether it would happen again.