Matt Mulhern (born July 21, 1960 in Philadelphia, Pennsylvania, USA) is an American actor who has starred in such films as One Crazy Summer and Biloxi Blues, and such television series such as Major Dad, JAG, and Rescue Me (playing Lt. John Stackhouse).
On TV, Mulhern played the Lieutenant on the top ten CBS hit Major Dad. Past guest appearances include NBC's Third Watch, Law and Order, Law and Order: Criminal Intent, Law and Order: Special Victims Unit, a recurring role on FX's Rescue Me, and appearances on Fox's Fringe, CBS's CSI, NBC's The Education of Max Bickford, NBC's Ed, and CBS's Blue Bloods.
He has written and directed two films, Walking to the Waterline, which he also acted in, and Duane Hopwood, starring David Schwimmer, which was named one of 2005's best films by Roger Ebert.
