John Thaddeus Filmography
| 2022 | As We See It (TV Series) · as Loud Grandfather |
| 2019 | Nation's Fire · as Homeless Vet |
| 2016 | Goliath (TV Series) · as Horseman #1 |
| 2015 | Wicked City (TV Series) · as Whiskey Owner |
| 2014 | How to Get Away with Murder (TV Series) · as Cabbie |
| 2014 | |
| 2011 | Harry's Law (TV Series) · as Officer Patrick Fox |
| 2010 | Rizzoli & Isles (TV Series) · as Chuck Fletcher |
| 2008 | Raising the Bar (TV Series) · as Joseph Duncan |
| 2008 | IQ-145 (TV Series) |
| 2008 | Tiny Little Lies · as Michael |
| 2007 | |
| 2006 | Heroes (TV Series) · as Prison Guard |
| 2005 | Criminal Minds (TV Series) · as Robert Matthew Burke |
| 2005 | McBride: It's Murder, Madam · as Nick |
| 2004 | Boston Legal (TV Series) · as Detective John Stephenson |
| 2003 | NCIS (TV Series) · as Lane Harrison / Lane Danielson / Billy Collins |
| 2003 | Miracles (TV Series) · as Detective Krantz |
| 2002 | American Dreams (TV Series) · as Mr. La Padura |
| 2002 | Without a Trace (TV Series) · as Ken Hammond |
| 2002 | CSI: Miami (TV Series) · as Paul Donlan |
| 2002 | Firefly (TV Series) · as Stark |
| 2001 | Octopus 2: River of Fear · as Tony |
| 2001 | 24 (TV Series) · as Joe Prado |
| 2001 | The Guardian (TV Series) · as Det. Craig Rolsky |
| 2001 | The Division (TV Series) · as Joe |
| 2000 | Boston Public (TV Series) · as Joe |
| 1998 | Charmed (TV Series) · as Stan Provazolli |
| 1998 | Snake Eyes · as Cop #2 |
| 1997 | Ally McBeal (TV Series) · as Michael Young |
| 1997 | The Practice (TV Series) · as Denny Staples |
| 1996 | Nash Bridges (TV Series) · as Tommy Krell |
| 1995 | Star Trek: Voyager (TV Series) · as Krenim Officer |
| 1994 | ER (TV Series) · as Keith Nelson |
| 1993 | Diagnosis Murder (TV Series) · as Detective Robert Cardinal |
| 1993 | NYPD Blue (TV Series) · as Bruce Clayton |
| 1993 | The Thing Called Love · as Country Dancer |
| 1993 | Walker, Texas Ranger (TV Series) · as Dean Scaggs |
| 1989 | Sea of Love · as Tommy |
| 1975 | Ryan's Hope (TV Series) · as Fritz (year Unknown) |
| 1973 | The Young and the Restless (TV Series) · as Joe Connors |
| 1970 | All My Children (TV Series) · as Blade |
| 1968 | One Life to Live (TV Series) · as Tony (year Unknown) |
| 1965 | Days of our Lives (TV Series) · as Kidnapper |
| 1952 | Guiding Light (TV Series) · as Jailwhaler |
| 2025 | High Ground · as Screenplay |
| 2021 |
| 2022 | Frank and Penelope · as Original Story |