Bud Abbott and Lou Costello frequently used him as a form of "court jester" on the set of their films. It was his job to keep the energy level up through a series of pranks and practical jokes. He would even suddenly appear on camera during a take to break up the cast and crew. In Bud Abbott Lou Costello Meet Frankenstein (1948), Lou answers a knock at the door expecting to see large actor Lon Chaney Jr. Instead, the very short Barber walks in wearing a funny hat with a feather. In another outtake from that film, Bela Lugosi, in full Dracula regalia, is solemnly descending a staircase to meet Bud and Lou when all of a sudden the actors and crew burst out laughing. Lugosi, annoyed, turns around to see Barber following right behind him, mimicking his steps. Barber also appeared in bit parts, such as a delivery boy, waiter or bellhop, in many of Abbott and Costello's films, and played many different characters--often just walk-ons, sometimes just a picture of him on a wall or a "wanted" poster of him in a Post Office--in their TV series. His final film appearance was in Lou Costello's last picture. The 30 Foot Bride of Candy Rock (1959). His film career included bit parts in over 100 (known) feature films.