Alex Lawther

Lawther was born in Winchester, Hampshire and raised in Petersfield. He is of English and Irish descent, possessing dual British and Irish citizenship through his Northern Irish father. The son of two lawyers, Lawther has described himself as having come from a "white middle-class bubble". As the youngest of three children, he said that his aspiration to be an actor came from having to make up his own games to entertain himself as a child. Both of his siblings live and work in the United States, with his older brother, Cameron Lawther, being an award-winning Hollywood film producer, and his older sister Ellie Lawther working in public policy.

Lawther was educated at Churcher's College, a selective independent school in Petersfield. After getting into trouble for creating an illegitimate drama club at his school with friends, Lawther became heavily involved in the drama programme when an official one was started. He played Ratty in The Wind in the Willows, Sir Toby Belch in Twelfth Night, and Lucas in The Third Bank of the River, and received the Sir Daniel Day-Lewis Award by the Petersfield Town Council. In 2009, a fourteen-year-old Lawther was allowed to write and direct his own full-length play based on a song by Sara Bareilles entitled Rejected Fairytales as part of his drama club involvement, where he received laudatory coverage in the local press as a "theatrical whiz kid" who would end up working as an actor in the West End.

In 2010, he was accepted into the prestigious National Youth Theatre, where he received his only formal training as an actor. He also collaborated with his brother as an actor on his short film The Fear, made when the elder Lawther was applying to film school. He did not study drama at GCSE or A level. He initially planned to read History at King's College London, but ultimately gave up his place after being cast in The Imitation Game; instead, he moved to London at 18 to pursue acting professionally.