Monaghan first gained fame as Hetty Wainthropp's sidekick Geoffrey in "Hetty Wainthropp Investigates" (1996–1998). His first film role was as Sasha in the television film "Hostile Waters" (1997) based on the true story of a Russian and an American submarine colliding in the Cold War. His other film roles include playing the young mutant Chris Bradley formerly known as Maverick in the superhero film ' (2009) and playing Beaumont Kin in ' (2019), reuniting with J.J. Abrams, the co-creator of "Lost." He also has hosted the nature programme "Wild Things with Dominic Monaghan" (2012–2016).