Monaghan began starring as Ian Gallagher in the series Shameless in 2011. He has also had recurring roles in the TV series Gotham as Jerome Valeska in 2015 and in the series Mercy Street as Tom Fairfax in 2016. Monaghan has starred in the movies Click, The Santa Clause 3: The Escape Clause, The Three Investigators and the Secret of Skeleton Island, Dog Gone, Safe Harbor, Another Harvest Moon, Prom, Jamie Marks Is Dead, Vampire Academy, and The Giver. In 2005 he won a Young Artist Award for Malcolm in the Middle.
