Movies:
* The China Syndrome (1979) - Peter, a power plant worker
* The Jewel of the Nile (1985) - The American Ambassador
* Predator (1987) - Captain George Dillon
* The Abyss (1989) - Lieutenant Hiram Coffey
* The Rocketeer (1991) - Neville Sinclair
* The Santa Clause (1994) - Neil Miller
* The Santa Clause 2 (2002) - Neil Miller
* The Santa Clause 3: The Escape Clause (2006) - Neil Miller
* The Lost World: Jurassic Park (1997) - John Hammond's Assistant
* The Faculty (1998) - Coach Willis
* The Thirteenth Floor (1999) - Dr. Douglas Hall
* The General's Daughter (1999) - Captain Bill Burgess
* The Green Mile (1999) - Percy Wetmore
* Frequency (2000) - John Sullivan
* The Time Machine (2002) - Dr. Goosmann
* The Cave (2005) - Jack
* Transformers (2007) - Glen Whitman
* The Princess Diaries 2: Royal Engagement (2004) - Lord Devereaux
Television:
* The Rockford Files (1978-1980) - various roles
* The A-Team (1983-1987) - various roles
* Magnum, P.I. (1980-1988) - various roles
* Hill Street Blues (1981-1987) - various roles
* Miami Vice (1984-1989) - various roles
* Quantum Leap (1989-1993) - various roles
* L.A. Law (1986-1994) - various roles
* The X-Files (1993-2002) - various roles
* ER (1994-2009) - Dr. David Morgenstern
* Star Trek: Voyager (1995-2001) - various roles
* JAG (1995-2005) - various roles
* CSI: Crime Scene Investigation (2000-2015) - various roles
* Without a Trace (2002-2009) - various roles
* The Mentalist (2008-2015) - various roles
* NCIS (2003-present) - various roles
* Castle (2009-2016) - various roles
* The Good Wife (2009-2016) - various roles
* Scandal (2012-2018) - various roles
* Grey's Anatomy (2005-present) - various roles
* Suits (2011-2019) - various roles
* The Blacklist (2013-present) - various roles
* Supernatural (2005-2020) - various roles
This is not an exhaustive list, but it covers many of his most notable roles in film and television. He has also appeared in numerous other projects, including TV movies, miniseries, and theatre productions.