Nicholas Lea’s first major role was on the TV series The Commish, where he played Officer Enrico Caruso from 1991 to 1994.
It was during this time that he had a minor guest role in a first-season episode of The X-Files called “Gender Bender”. The producers were impressed by his performance and when, in the second season, he auditioned for the role of turncoat FBI agent Alex Krycek, he was successful.
Krycek became a popular character among fans. Because of his character’s willingness to switch sides, he was known as the “ratboy”. In the season three episode “Apocrypha,” Krycek was left to die in an abandoned missile silo with an alien ship. This allowed Lea to take a starring role in the series Once a Thief — which followed the 1996 John Woo film. Lea continued to play Krycek, who became a nemesis not just of Mulder and Scully but particularly of A.D. Skinner (Pensacon 2017 guest Mitch Pileggi).
In 2006, Lea had a role on ABC Family’s Kyle XY (26 episodes) playing Tom Foss, Kyle’s tutor, and was one of the lead actors (playing Ethan McKaye) on the Canadian TV series Whistler. He was also that series’ associate producer.
In 2012, he appeared as Agent Gardiner in SyFy’s Continuum and in 2013 in The Killing as Dale Daniel Shannon.
He has guest starred in shows such as NYPD Blue, Andromeda, Burn Notice, Sliders, Highlander: The Series, Judging Amy, CSI (as Catherine Willows’ boyfriend), and Men in Trees as Eric, the minister.
Nicholas has also starred in the ABC remake of the sci-fi series V. In 2012 he portrayed Eliot Ness, who formed the law enforcement group the Untouchables, in the Supernatural episode “Time after Time”. Lea also had a role on Arrow as Mark Francis, Moira Queen’s campaign manager.