He is known for his roles as Jackie Willow in Francis Ford Coppola's Gardens of Stone (1987), Lt. Phil Lowenthal in Memphis Belle (1990), and Travis Walton in Fire in the Sky (1993).

[2] In 1990, Sweeney starred as Treplev in Jeff Cohen's contemporary adaptation of Anton Chekhov's classic The Seagull at a small Off-Broadway theater (the RAPP Arts Center) in New York's Alphabet City neighborhood.

In films, he has played Jackie Willow, a Vietnam-era soldier, in Francis Ford Coppola's Gardens of Stone (1987), navigator 1st Lt. Phil Lowenthal in Memphis Belle (1990), and Travis Walton in Fire in the Sky (1993).

He also played former ice hockey player Doug Dorsey in The Cutting Edge (1992), Shoeless Joe Jackson in Eight Men Out (1988), and Dish Boggett in Lonesome Dove (1989).

Marshal Sam Kassmeyer, assigned to protect Haley and Jack Hotchner on Criminal Minds (2009); as Peter Emory in season 1 of Crash (2008);[1] as Carter in The Event (2010); and as Larry on Two and a Half Men (2013-2014).

He is currently the voice-over artist for the OWN: Oprah Winfrey Network, and his large body of voiceover work includes three seasons of Fox Sports Net's Beyond the Glory and National Geographic Television's Ice Pilots.