Along with co-star Glenn Close, she appeared in all of the show's fifty-nine episodes.
Byrne has also starred in the films Troy, 28 Weeks Later, Knowing, Insidious, X-Men: First Class, X-Men: Apocalypse, as well as the comedies Bridesmaids, Neighbors, and Spy.
She is the youngest of their four children; she has an older brother, George, and two older sisters, Alice and Lucy.
In a 2009 interview, Byrne stated that her mother is an atheist, while both she and her father are agnostics.
My Mother Frank, and Clara Law's The Goddess of 1967, the last of which gained her the Volpi Cup for "Best Actress" at the 2000 Venice Film Festival.
Byrne revealed in a post-award interview that, prior to winning the Venice Film Festival award, she was surprised by her own performance and found it confronting watching the film because her acting was "too depressing".
Byrne appeared with Snoop Dogg in Danny Green's film The Tenants, based on Bernard Malamud's novel, and starred as Alex with Josh Hartnett and Diane Kruger in the romantic psychological thriller Wicker Park.