James Montgomery Doohan ( March 3 , 1920 -- July 20 , 2005 ) was a Canadian actor famous for his role as Montgomery `` Scotty '' Scott in the television and movie series Star Trek . James Montgomery `` Jimmy '' Doohan ( ; March 3 , 1920 -- July 20 , 2005 ) was a Canadian character and voice actor best known for his role as Montgomery `` Scotty '' Scott in the television and film series Star Trek .