He is best known for being the second actor to portray Police Chief Derek Frye on All My Children (2004-2008). He also portrayed Master Chief Russ Jeter on the TNT show The Last Ship from 2014 to 2018. Parnell also acted in the films Top Gun: Maverick (2022), Mission: Impossible – Dead Reckoning Part One (2023), and The Killer (2023).