After graduating in 2008, Raine began a successful stage career, initially cast as Lesley Sharp's goth daughter in Simon Stephens's Harper Regan. She then played Tamsin Greig's 16-year-old daughter in David Hare's Gethsemane.

In radio, she has played Felice in the Murray Gold play Kafka the Musical, broadcast in April 2011 on BBC 3. She also played the part of Kasey in Ed Harris' radio play The Wire, the Wall., first broadcast in February 2011.

Raine then played at the National Theatre in Mike Bartlett's Earthquakes in London as teenage wild-child Jasmine; and then as a secretary in the revival of Clifford Odets's Rocket to the Moon. She has also appeared in Ghosts and Punk Rock, for which she won the Manchester Evening News Award for Best Supporting Actress. She played a role in the Young Vic's revival of Middleton and Rowley's 17th-century tragedy, The Changeling. In 2012 Raine starred in Beyond Ballets Russes at the London Coliseum.

Raine was a guest star in the 2013 Doctor Who episode "Hide". Later, she appeared as Doctor Who's original Producer, Verity Lambert, in the drama An Adventure in Space and Time, showing the creation of the series as part of its fiftieth anniversary celebrations.

In 2014 Raine joined the cast of the BBC2 police drama Line of Duty for series 2 as Detective Constable Georgia Trotman working for the AC12 anti corruption unit.

Raine began dating actor Tom Goodman-Hill in 2010 after they met while co-starring in a play. Goodman-Hill and Raine married on 1 September 2015.