Duff also landed a small part in George Lucas's 1980 blockbuster, Star Wars: Episode V The Empire Strikes Back, which today stands as the defining role of his career. Playing Echo Base Rebel officer Jeroen Webb on the ice planet Hoth, Duff appears fleetingly and without dialogue in the film's sequence in which actor Harrison Ford (Han Solo) departs the base atop a tauntaun mount in search of the missing Mark Hamill (Luke Skywalker), against the protests of base personnel.
Duff's film credit in The Empire Strikes Back, along with four other actors, lists him only as one of several "Other Officers" in the Rebel Forces. As such, this may create some ambiguity regarding which character Duff portrays in the film—indeed, among many Star Wars online fan sites, including Star Wars author Bob Vitas's now-defunct The Completely Unofficial Star Wars Encyclopedia, Duff is widely incorrectly credited as playing the role of Rebel officer Trey Callum, who, in fact, is played by stuntman Bob Anderson. Duff's role as Jeroen Webb was officially confirmed by a Lucasfilm publication in the 2010 book The Making of The Empire Strikes Back.
Duff's character, Jeroen Webb, was first provided a canon name and personal backstory through Decipher, Inc.'s 1996 Hoth Limited expansion set of the Star Wars Customizable Card Game.
- The Making of The Empire Strikes Back