He is known for his role as real life Navy SEAL Marc Alan Lee in the acclaimed film American Sniper.

[citation needed] Grimes has appeared in All the Boys Love Mandy Lane, War Eagle, Arkansas, and Assassination of a High School President, which received a limited release in March 2009.

He also appeared in the ABC drama Brothers & Sisters, as Ryan Lafferty, the illegitimate son of William Walker, patriarch of the show's family.

Reports, confirmed by BuzzFeed,[8] indicated that he quit because he refused to participate in same-sex kissing or sex scenes or to play a character that was attracted to men.

[10][11] Grimes played United States Navy SEAL Marc Lee, who was killed in action in 2006, in American Sniper (2014).