Actress. Born in Glasgow, Macdonald was raised in Newton Mearns (East Renfrewshire) and educated there at Eastwood High School. She was working as a bar-maid before auditioning for the role of schoolgirl Diane Coulston in Trainspotting (1996), based on the hard-hitting Irvine Welsh novel. She returned in T2 Trainspotting (2017). Macdonald has starred films including My Life So Far (1999), Two Family House (2000), Gosford Park (2001), the J.M. Barrie bio-pic Finding Neverland (2004), Lassie (2005), Nanny McPhee (2005), A Cock and Bull Story (2006), Anna Karenina (2012), Swallows and Amazons (2016) and Goodbye Christopher Robin (2017). Her role in the BBC television film The Girl in the Café (2005) brought her a nomination for a Golden Globe Award in 2006. She also starred in the HBO crime drama Boardwalk Empire (2010-14) which brought two further Golden Globe nominations, and an Emmy nomination.
In 2003, Macdonald married Dougie Payne (b.1972), bass-player in the band Travis but the couple separated in 2017. She lives in Glasgow with her children.