Wenham started his career as an actor after graduating from Theatre Nepean at the University of Western Sydney with a Bachelor of Arts (Performing Arts) in 1987. Wenham's television credits include several telemovies, such as his AFI award-winning role in the 1997 telemovie "Simone de Beauvoir's Babies"; and his role as the outwardly laid back but deeply enigmatic diver Dan Della Bosca in the 1998 and 1999 seasons of the highly successful ABC television series "SeaChange". His role as "Diver Dan" has made the actor something of a sex symbol, although he dislikes thinking of himself as such, and he has been voted Australia's "sexiest man alive". A portrait of Wenham by artist Adam Cullen won the Archibald Prize in 2000.