A member of Screen Actors Guild, AFTRA, and Actors' Equity, Marshall has appeared in major roles on several projects, including Captain Richard Phillips in "Somali Pirate Takedown: The Real Story" for Discovery Channel. Other leading roles include FDNY Captain Jay Jonas in the Emmy Award-nominated "Countdown to Ground Zero" for the History Channel and a recurring role as John Zaffis in "A Haunting" for the Discovery Channel. Stage work includes both the Off-Broadway and Baltimore Hippodrome productions of Ken Davenport's hit interactive comedy "The Awesome 80s Prom" as the overbearing Principal Snelgrove. Marshall is also a member of the Dramatists Guild, and his play "41N 50W" had its world premiere in October 2012 at London's St. James Theatre.