Lupus played Willy Armitage in the original Mission: Impossible television series in the 1960s. Armitage was the Impossible Missions Force's muscle man, and featured in nearly all episodes of the series. The character of Willy Armitage was the strong, silent type, usually with very little dialogue. Late in the show's run during season five, the producers decided his character was superfluous and he was dropped to recurring status, appearing in a little over half of that season's episodes. Fan outcry and the lack of success in finding a replacement for his character resulted in his return to regular status the following season and getting a greater role in the stories, often assuming roles as a convict or thug. Only Lupus and Greg Morris sustained a regular role through the show's entire run, although Morris appeared in more episodes.