The most successful M \* A \* S \* H spin-off was Trapper John , M.D. , a spin-off of the movie . It starred Trapper John McIntyre ( Pernell Roberts ) , but never talks about anything from the movie . Trapper John , M.D. featured the character of Trapper John McIntyre , played by Pernell Roberts , twenty-eight years after the events of the M \* A \* S \* H film and television series .