Oscar Desgagnés was born in Montreal, and is the son of Catherine De Seve and fine art photographer Frank Desgagnes.

He started acting when he was 11 years old, playing Fred Pellerin, who is his favorite storyteller, in L'Arracheuse de temps (2021) which was directed by Francis Leclerc.

In Plan B (2017), Oscar played the child version Jesse, who was played as an adult by Pier-Luc Funk, and his lead role as Max in the feature film Coco Ferme (2023) confirmed Oscar's love of storytelling and acting.

Oscar will next be in movie theatre in 2024 in Chien et chat (2024), Reem Kherici's next film, which is distributed in France by Gaumont.

He is passionate about soccer and is smart and funny.