John F. Showalter is an American television director, producer and editor.
During his adult life, Showalter became a television director and editor. His first work was the TV documentary series Time Machine, during which he was a consulting producer for a 1991 episode. Showalter's directing credits include episodes of Criminal Minds, Ghost Whisperer, House, Without a Trace (for which he was also a producer or an editor for other episodes), Supernatural, and The Mentalist. His editing credits include episodes of Lois & Clark: The New Adventures of Superman, Glory Days, Gideon's Crossing (which he was also a consulting producer for), Turks, and Who Wants to Marry My Dad?, as well as the shorts Ink and A Question of Loyalty.