[1] Grenier made his professional debut playing with EC Red Bull Salzburg of the Austrian Hockey League during the 2012–13 season.

[5] He was assigned to AHL affiliate, the Springfield Thunderbirds for the duration of the 2017–18 season, notching a professional high 20 goals in amassing 44 points in 72 games.

[citation needed] Having left the Panthers organization as a free agent, Grenier signed a one-year AHL contract with his hometown club, the Laval Rocket, on July 1, 2018.

[7] After agreeing to a one-year contract extension with the Roosters, on February 3, 2020, Grenier joined Lausanne HC on loan to provide depth for the final playoffs push.

[8] Following a return to the DEL with Eisbären Berlin, Grenier left after one season and moved to fellow German club, Kölner Haie, on July 21, 2023.