He trained at the Center for Speech and Drama at the University of London. His role in the play Kes at Manchester's Royal Exchange Theatre in 2004 earned him Best Newcomer awards from the Manchester Evening News and the Evening Standard Theatre.
He won a British Academy Television Award for Best Actor for his role in the 2007 film Boy A.
He began a relationship with Shannon Woodward in 2008, and in 2011 he began dating his Amazing Spider Man co-star Emma Stone. He and Stone split up in October of 2015. He and model Christine Gabel later began dating. In January 2022, he began a relationship with Alyssa Miller but they later split in spring 2022. He has a brother named Ben Garfield.