After his discharge from the army, Frankham worked first as a news reader, and then a writer, interviewer and producer for the BBC from 1948 to 1955.
He soon found work, appearing on five episodes of the live television program Matinee Theatre.
He worked steadily in television, as well as appearing in films such as Return of the Fly (1959), Ten Who Dared (1960), Master of the World (1961), Tales of Terror (1962), The Spiral Road (1962), King Rat (1965), and The Great Santini (1979).
Frankham provided the voice of Sergeant Tibbs the cat in Walt Disney's One Hundred and One Dalmatians (1961).
His career peaked in the 1960s with frequent roles on such shows as Thriller, GE True, Twelve O'Clock High, The F.B.I., Gomer Pyle, U.S.M.C., The Beverly Hillbillies, The Outer Limits, Star Trek (episode "Is There in Truth No Beauty?