Biography
William Duffy is an actor.

Acting
William Duffy is an actor.

A West Wing Special to Benefit When We All Vote· 2020
Larry

The Ascent· 2010
Thomas Shaw

Karla· 2006
Detective Porter

Waist Deep· 2006
Newscaster #2

Sniper 3· 2005
Richard Addis

Blast from the Past· 1999
Workman #1

Double Tap· 1997
Gas Man

Betrayed by Love· 1994
Paxton

The Two Jakes· 1990
Desk Sergeant

Loving· 1970
Jay

Brainstorm· 1965
Orderly (uncredited)

Bosch· 2015
Vault Attendant

Scandal· 2012
Ralph Greenwald

Parenthood· 2010
Mr. Carlson

The Mentalist· 2008
TSA Agent #2

Carpoolers· 2007

Heroes· 2006
ER Doctor

Criminal Minds· 2005
Dr. Larson

It's Always Sunny in Philadelphia· 2005
Hedge Fund Guy

NCIS· 2003
Harris Cobb

The O.C.· 2003
(voice)

American Dreams· 2002
Father Gregory

The Division· 2001
Commander Jackson

The West Wing· 1999
Staffer

Hearts Afire· 1992
Doctor

Beverly Hills, 90210· 1990
Doorman

Law & Order· 1990
CSU Technician