She made her first onscreen appearance at the age of 10 in the 1992 television adaptation of The Camomile Lawn, directed by her father, Peter Hall.

Her professional stage debut came in her father's 2002 production of Mrs. Warren's Profession, which earned her the Ian Charleson Award.

In 2008, she starred in Woody Allen's romantic comedy Vicky Cristina Barcelona, for which she received a Golden Globe nomination for Best Actress.

She won the British Academy Television Award for Best Supporting Actress for the 2009 Channel 4 miniseries Red Riding: 1974.

[12] She was a member of the Marlowe Society and performed in several productions alongside her housemate Dan Stevens, an English literature student at Emmanuel College.

[13][14] Hall's first professional role came in 1992, when at the age of nine she appeared as young Sophy in her father's television adaptation of Mary Wesley's The Camomile Lawn.

[17] Her performance was well-received,[17] and she was nominated for the Golden Globe Award for Best Actress – Motion Picture Musical or Comedy.

In 2008, she appeared in Ron Howard's historical drama Frost/Nixon as the girlfriend of David Frost, played by Michael Sheen.

[17] In June 2010, she won the British Academy Television Award for Best Supporting Actress for her portrayal of Paula Garland in the 2009 Channel 4 production Red Riding: In the Year of Our Lord 1974.

"[21] She starred in the BBC/HBO/VRT production of Parade's End (2012) opposite Benedict Cumberbatch, which earned her a BAFTA Television Award nomination for Best Actress.

[27] After re-reading accounts related to allegations of sexual abuse against Woody Allen, Hall in January 2018 donated her salary to Time's Up.

[33] Hall made her professional stage debut in 2002 when she starred as Vivie in her father's production of Mrs. Warren's Profession at the Strand Theatre in London.

[46] In 2008–2009, Hall appeared in Sam Mendes's first instalment of the Bridge Project as Hermione in The Winter's Tale and as Varya in The Cherry Orchard.

The Roundabout Theater production, directed by Lyndsey Turner, began previews on 20 December 2013, with the official opening on 16 January 2014 at the American Airlines Theatre.

[50] In 2010, there was intense media speculation of an affair between Hall and director Sam Mendes, who was married to Kate Winslet at the time.