Martin Balsam was the first of three actors who portrayed Dr. Rudy Wells. A well-known character actor, Balsam's previous film credits included films such as Breakfast at Tiffany's. In 1966, Balsam won the Best Supporting Actor Academy Award for A Thousand Clowns, and was also nominated for a 1977 Emmy for his performance in Raid on Entebbe.
Although Balsam officially appeared only the one time, footage of him as Rudy Wells can be seen in the opening credits of the telefilms Wine, Women and War and The Solid Gold Kidnapping, even though Wells is played by Alan Oppenheimer in the movie. To a lesser extent, Balsam can be glimpsed throughout the series in the show intro.
According to The Bionic Book, when the original pilot film was later re-edited for syndication as "The Moon and the Desert", Universal Studios brought Balsam back to record new narration as Rudy Wells.