Ed McMahon (March 6th, 1923 – June 23rd, 2009) appeared as himself on Scrubs.
Ed McMahon, born Edward Peter Leo "Ed" McMahon Jr., was an American announcer, celebrity, comedian, and game show host. He is most famous for his work on TV as Johnny Carson's announcer/sidekick on The Tonight Show from 1962 to 1992.
In the Scrubs episode "My Roommates", as a recently homeless J.D. is looking for Doug's apartment, he accidentally knocks on Ed McMahon's door. Ed tells him he has to "go change someone's life", and carries a large check out of his apartment.