Born and raised in Berlin, this adorably scruffy actor played the adolescent sidekick to an elderly detective on the British TV show Hetty Wainthropp Investigates in 1996. Five years later, Monaghan graduated to the big time as a cheerfully mischievous hobbit in The Lord of the Rings trilogy. Soon after, he shot to stardom as Charlie Pace, a sensitive junkie rock star on Lost. With this role, he won the hearts of viewers and his costar Evangeline Lilly, with whom he's had an on-again, off-again relationship. A few years after his character was killed off of Lost, he was back on another TV mystery, FlashForward, portraying quantum physicist Simon Campos. While filming Lost in Hawaii, Monaghan had plenty of opportunities to do some surfing, one of his favorite pastimes. But his appreciation for nature and the outdoors extends beyond indulging in sports: as an animal-rights supporter, he believes in preserving the environment for wildlife.
Lived in Germany as a child because his father, a science teacher, taught courses for British troops stationed there; moved with his family to Britain at 12 years old.
Got his start in show business acting in a youth theater group in 1995 in Manchester, England, a year before he was cast in the BBC's Hetty Wainthropp Investigates (which is set in the Manchester area).
Is an avid admirer of John Lennon; a lyric by Lennon, "living is easy with eyes closed," is tattooed on his arm (Lennon was murdered on Monaghan's birthday).