Born in New Jersey to an MTV producer father, Liam Aiken made his professional acting debut in a Ford Windstar commercial. Liam made his stage debut in the Broadway play A Doll's House at the age of seven and his film debut playing Parker Posey's son in Henry Fool in the same year. It was because of his need of a college fund, that his mother encouraged Aiken to become an actor. His first major film role was playing Susan Sarandon's young son in Stepmom as Ben Harrison in 1998. He also appeared as Tom Hanks' doomed younger son in the 2002 film Road to Perdition. He starred in the family film Good Boy! playing the lead, Owen Baker, in 2003. He turned down the role of Cole Sear in The Sixth Sense, because his mother felt he was too young for the death-fixated role. Fellow actor Haley Joel Osment then received the part. Liam was also considered for the role of Harry Potter as he had previously worked with director Chris Columbus, but he was unable to take the part as he was not from the British Isles.
Liam's remarkable acting skills have earned him critical acclaim as well as nominations (and at least one award) aimed at recognizing young acting talent.
He attends the esteemed Dwight-Englewood School, from which he will graduate in 2008.
In December 2004, he was seen in one of his more recognized roles as Klaus Baudelaire, the orphaned, avid reader in the film A Series of Unfortunate Events with Jim Carrey based on the popular books of the same name.
- Lemony Snicket's A Series of Unfortunate Events (2004) - Klaus Baudelaire
- Good Boy! (2003) - Owen Baker
- Road to Perdition (2002) - Peter Sullivan
- The Rising Place (2001) - Emmett Wilder
- Sweet November (2001) - Abner
- I Dreamed of Africa (2001) - Young Emmanuele
- Stepmom (1998) - Ben Harrison
- Henry Fool (1997) - Ned
- Height: 5 Feet and 9 Inches
- An only child
- Liam was 2 years old when his father passed away (his father was 34)
- Plays electric and acoustic guitar
- Plays the Drums
- A fan of punk music and aspires to play the guitar like Rage Against the Machine's Tom Morello.
- Favorite movies are The Sting and The Italian Job
- Given his first dog, an Italian Greyhound which he named Kes (after the kestrel in Kes), from the crew of Good Boy!