Asa Butterfield was born in Islington, London, and is the son of Jacqueline Farr and Sam Butterfield.

Butterfield first started acting at the age of 7 on Friday afternoons after school at the Young Actors' Theatre, in his hometown. Later, he secured minor roles in the 2006 television drama After Thomas and the 2007 film Son of Rambow. In 2008 he also had a guest role playing Donny in Ashes to Ashes.

In that same year, aged 10, he played the lead role in The Boy in the Striped Pyjamas. Director Mark Herman said that they came across Butterfield early on in the audition process. He was on the first audition tape he received and he was the third hopeful he met in person. Herman thought Butterfield's performance was outstanding, but only decided to cast him after auditioning hundreds of other boys, "so no stone was left unturned".

Producer David Heyman and director Mark Herman were looking for someone who was able to portray the main character's innocence, so they asked each of the children what they knew about the Holocaust. Butterfield's knowledge was slim and it was purposely kept that way throughout filming so it would be easier for him to convey his character's innocence. The final scenes of the film were shot at the end of the production period to prepare both him and Jack Scanlon for the dramatic ending of the film. He beat hundreds of boys to the role and also successfully passed the auditions for a role in Mr. Nobody for which he auditioned at the same time. He chose not to pursue the latter role.

In 2008, Butterfield appeared in the Merlin episode "The Beginning of the End"; he played a young druid boy sentenced to death by Uther Pendragon because he feels threatened by the boy's magic. Despite the Great Dragon's advice and the warning that Arthur cannot survive if the boy does, Merlin and Arthur, with the help of Morgana, help the boy escape to rejoin the Druids. When they are about to disappear into the forest, Arthur asks him for his name, which he says is Mordred, an important character from the Arthurian legends who is supposed to kill King Arthur. Butterfield appeared as Mordred in a number of subsequent episodes; however the role has now been recast, with Alexander Vlahos playing Mordred as an adult character.

In 2010, he had a small part in The Wolfman. He starred as Norman Green at the age of 12 in Nanny McPhee and the Big Bang (2010), working together with Emma Thompson. The film, and his performance, both received positive reviews. At the age of 13 he played the main and title character in Martin Scorsese's Hugo, adapted from the novel The Invention of Hugo Cabret. Hugo was filmed from June 2010 to January 2011, it was released on 23 November 2011, and achieved critical and box-office success. Butterfield played the title role of Andrew "Ender" Wiggin in the film adaptation of the Orson Scott Card novel Ender's Game, which completed filming in the first half of 2012, and was released in 2013.

Later in 2013, Butterfield was reported to be in talks for a role in King of Kastle alongside Clive Owen and in May, he was cast in The White Circus with his fellow cast member from Hugo, Chloe Grace Moretz. In early 2014, Butterfield was cast in a film adaptation of Ten Thousand Saints alongside Hailee Steinfeld and Ethan Hawke as Hawke's son who's addicted to drugs. Shooting began on 27 January 2014 and the film is set to be released in 2015.