His high-concept science fiction films tend to explore social, cultural and political issues; artificial realities, simulations and the male gaze are frequent themes in his work.

He left New Zealand at age 21 and began directing TV ads in London, which he did for more than ten years before his directorial debut, Gattaca (1997).

Niccol has directed the films Gattaca (1997), Simone (2002), Lord of War (2005), In Time (2011), The Host (2013), and Good Kill (2014) (reuniting after 17 years with actor Ethan Hawke in a lead role; Hawke also appeared in Lord of War as a supporting character named Jack Valentine).

[10][11] In response to public backlash, Niccols confirmed that the film's development had been put on hold until a full consultation with the New Zealand Muslim community had been conducted.

[12][13] Niccol's breakthrough screenplay was his script for the film The Truman Show (1998), directed by Peter Weir and starring Jim Carrey.