In addition to Trelane, Campbell also portrayed the Klingon Captain Koloth in the classic (and most famous) Star Trek episode entitled "The Trouble with Tribbles". Campbell reprised his role of Koloth in an episode of "Star Trek: Deep Space Nine" which was entitled "Blood Oath" and aired in 1994.
William Campbell also starred in director Francis Ford Coppola's first legitimate (non softcore porn) film entitled "Dementia 13". The film was produced by Roger Corman. Campbell is also known for his role as Jerry Austin in "Cannonball" from 1958-1959 and for "The Return of the Six-Million-Dollar Man and the Bionic Woman". In addition to "Star Trek", Cambell guest starred on many classic shows including "Perry Mason", "The Wild Wild West", "Bonanza", "Combat!", "Ironside", "Emergency!", "Adam-12", "Gunsmoke", "The Streets of San Francisco", "Shazam!", "The Hardy Boys/Nancy Drew Mysteries", "Quincy M.E." and "Kung Fu: The Legend Continues".
William Campbell loved "Star Trek" fans and they loved him. He loved sharing his "Star Trek" stories with attendees at the Star Trek and Sci-Fi conventions he attended. Campbell has had health problems since the early 2000s but still found the strength to attend the 40th anniversary Star Trek convention in 2006 which was held by Creation in Las Vegas. He was a very talented and nice man. He will be missed.