Akhtar was born in London, to a Pakistani father and a Kenyan mother. His sister Sadia Akhtar is seven years older than him. He was educated at Cheltenham College Junior School from 1991 to 1994 and then moved to Cheltenham College in Newick House from 1994 to 1999. He originally completed a degree in law, but decided to follow his passion and change to acting, training at the Actors Studio Drama School in New York.

Akhtar has also won acclaim for his dramatic performances: in 2015, he was nominated for a BAFTA for Best Supporting Actor for his 2014 role as Wilson Wilson on Channel 4's Utopia. He played shopkeeper Ahmed alongside Toby Jones in the BBC mini-series Capital, and DS Ira King in the BBC's River. Reviewing River in The Daily Telegraph, Michael Hogan wrote, "This series was beautifully written by Abi Morgan, stylishly directed, and most of all, superbly acted. The quieter, less showy supporting players also shone. Not just stalwarts [...] but fresher faces: Adeel Akhtar as River's endlessly patient sidekick and Georgina Rich as his psychiatrist".

In 2016 Akhtar appeared as Shahzad in the BBC one-off drama Murdered by My Father. He won the 2017 BAFTA award for Lead Actor for this role - the first non-white actor to do so. He also appeared as Rob Singhal in the acclaimed BBC miniseries based on John Le Carre's The Night Manager.