Aird was spotted by a casting director at age nine whilst at Bush Davies Ballet School and starred in the 1980 dramatisation of the H. G. Wells novel The History of Mr Polly.
In 1981, she portrayed the young Elspeth Huxley in the television adaptation of the latter's autobiographical book The Flame Trees of Thika.
She starred in the 1997 film Fever Pitch alongside Colin Firth, and in 2000 as forensic pathologist Frankie Wharton in Waking the Dead.
[2] Aird has done voiceover for various BBC natural history projects (including Wild Mallorca) as well as various TV advertisements.
Aird has one son with James Purefoy,[3] and one daughter with husband Toby Merritt.