Movies:
* The Big Lebowski (1998) - as "Walter Sobchak" - perhaps his most iconic role
* Down Periscope (1996) - as "Chief Petty Officer 'Walleye' Walters"
* Beverly Hills Cop (1984) - as "Victor"
* The Frighteners (1996) - as "Ray Parker"
* The Astronaut's Wife (1999) - as "Dr. Dave Gamble"
* The Lost Boys (1987) - as "Dwayne"
* Red Dawn (1984) - as "Jed Eckert"
* The Abyss (1989) - as "Lt. Commander Coffey"
* The Last Boy Scout (1991) - as "The Sweeper"
* The Glimmer Man (1996) - as "Jimmy 'The Chin' Ferrara"
Television:
* The Pretender (1996-2000) - as "Jarod" - recurring role
* Nash Bridges (1996-2001) - as "Lt. Evan Cortez" - recurring role
* The O.C. (2003-2007) - as "Dr. Neil Roberts" - recurring role
* CSI: Miami (2002-2012) - as "Frank Tripp" - recurring role
* ER (1994-2009) - as "Dr. David Morgenstern" - recurring role
* Grey's Anatomy (2005-2023) - as "Dr. Mark Sloan" - recurring role
* 24 (2001-2010) - as "Tony Almeida" - recurring role
* The X-Files (1993-2002) - as "Agent Michael Kritschgau" - recurring role
* Star Trek: Voyager (1995-2001) - as "Neelix" - recurring role
* The Twilight Zone (1985-1989) - as "The Man in the Mirror" - recurring role
Other Notable Appearances:
* Law & Order: Special Victims Unit
* Without a Trace
* Cold Case
* Criminal Minds
* Castle
* NCIS
* Hawaii Five-O
* The Mentalist
* Bones
* Leverage
* Psych
* Supernatural
This is not an exhaustive list, but it highlights some of the most notable and impactful projects Jon Gries has been involved in. He has enjoyed a long and diverse career, showcasing his versatility as an actor across a wide range of genres.