Johnny Kastl is an American lawyer and former actor, perhaps best known for his role as Dr. Doug Murphy on the medical comedy Scrubs.

He made cameo appearances in several Hollywood productions and played other parts on television, including the role of Todd Jaracki on The Beast.

He acted in many plays and was a co-founder and active member of a student sketch comedy group called "The Kaktabulz".

Kastl had a recurring role on Scrubs for 8 years from 2001 to 2009 as Dr. Doug Murphy, the totally incompetent doctor who finally finds his calling as a very competent forensic pathologist.

He is an avid golfer and won The Golf Channel's 2006 The Big-Break All Star Challenge Scrubs competition, beating out Robert Maschio ("The Todd") in the final match.