Boris Karloff acted solely in action films.
William Henry Pratt ( 23 November 1887 -- 2 February 1969 ) , better known by his stage name Boris Karloff , was an English actor who was primarily known for his typecast roles in horror films that depicted the characters Frankenstein and The Mummy . He portrayed Frankenstein 's monster in Frankenstein ( 1931 ) , Bride of Frankenstein ( 1935 ) , and Son of Frankenstein ( 1939 ) , which resulted in his immense popularity . Frankenstein is a 1931 American pre-Code horror monster film from Universal Pictures directed by James Whale and adapted from the play by Peggy Webling ( which in turn is based on the novel of the same name by Mary Shelley ) , about a scientist and his assistant who dig up corpses to build a man animated by electricity , but his assistant accidentally gives the creature an abnormal , murderer 's brain . The Mummy is a 1932 American pre-Code horror film directed by Karl Freund .