Her roles include Sister Clara in The Golden Compass (2007), Gale Benson in The Bank Job (2008), Alice in The Bletchley Circle (2012–2014), Ann in Mr. Holmes (2015), Rose Coyne in My Mother and Other Strangers (2016), Agathe/The Enchantress in Beauty and the Beast (2017), Corinne Aldrich in Luther: The Fallen Sun, Louise in Hijack, and Caroline Burkett in Fool Me Once.

She wanted to attend Newcastle University, but her father encouraged her to follow older sister Rebecca to New Hall, Cambridge,[5][6] from which she graduated with a BA degree in English in 2000.

[9] In July 2005, she appeared again at the National in Nick Dear's Power, staged in the Cottesloe Theatre[10] and also won acclaim at the West Yorkshire Playhouse, Leeds, in September 2005 playing Viola in Ian Brown's production of Twelfth Night.

Giving a career enhancing performance, she also played Elinor Dashwood in BBC One's three-part adaptation, by Andrew Davies, of Jane Austen's novel Sense and Sensibility, first broadcast on New Year's Day 2008.

[3] In July 2008, she returned to the National to appear in ...some trace of her, Katie Mitchell's adaptation of Dostoyevsky's The Idiot, co-starring Ben Whishaw at the Cottesloe Theatre,[17] while later in the year she played Mary in T.S.

From 29 June to 26 July 2012, she played the lead role of Nora, opposite Dominic Rowan's Torvald, in a new version of A Doll's House by Simon Stephens at London's Young Vic Theatre, in a production directed by Carrie Cracknell and designed by Ian MacNeil.

From 8 August to 26 October 2013, Morahan reprised her role as Nora Helmer alongside Dominic Rowan, who returned as her husband Torvald, at the Duke of York's Theatre London.