De Wolff, who mainly played villainous roles, began his long career in the 1930s, with one of earliest roles being in the film Fire Over England. His television credits included The Adventures of Robin Hood, The Avengers, Maigret, Danger Man, The Saint, Paul Temple and Dixon of Dock Green.
Other notable film appearances included Black Dog in Treasure Island, the Spirit of Christmas Present in Scrooge, Dr Mortimer in The Hound of the Baskervilles, the gypsy leader Vavra in From Russia With Love and Agrippa in Carry On Cleo. He also played the villian Jedikiah in The Tomorrow People and Simon the Pharisee in the miniseries Jesus of Nazareth.
- Internet Movie Database at the