Pettyfer was raised in Windsor, Berkshire, and attended Shiplake College boarding school near Henley-on-Thames in Oxfordshire and Lambrook Haileybury School in Windsor. He initially attended Millfield School in Somerset, before Shipklake College, and then left after GCSEs to attend drama college. When not working, Pettyfer’s hobbies include skiing and hockey. He also attended Sylvia Young Theatre School.

After Pettyfer completed filming Stormbreaker, he did not discuss the film with anyone at his school, citing the advice of his Stormbreaker co-star, Ewan McGregor, who told him to keep his personal and professional life separate. Pettyfer has since decided to leave school and concentrate on his film career, whilst studying drama at college, saying that “When you have already experienced going out and working in the real world, and you come back to school, you just see it as a playground and you don’t want to be there any more”.

Pettyfer has seven tattoos, including a Celtic cross on his chest, Arabic script on the inside of his right arm, the words, “What Goes Around Comes Around” on his right shoulder, a Kanji script on his lower waist, and the letters “ER,” the initials of his now ex-girlfriend Emma Roberts inside interlinking hearts on his right wrist. When Contactmusic asked him about the “ER” tattoo he said “I don’t know how to say it, she’s a lovely, lovely girl, we had a spell of something that is over now, but we’re on good terms. She’s beautiful, she’s great; we’re really good friends.” The actor had gotten Roberts’ name tattooed on his wrist while the two were dating. “I’m going to get asked about this, aren’t I? I thought it was just between me and her,” he said when asked about the tattoo.