Notable roles have included the title-roles in Gloriana and Maria Stuarda, Dido in Les Troyens and Baba the Turk in The Rake's Progress.
In 1989, Walker, along with June Anderson (Coloratura Soprano), Klaus König (tenor), and Jan-Hendrik Rootering (bass-baritone), under the baton of Leonard Bernstein, gave a performance of Beethoven's 9th Symphony.
She spectacularly performed Rule Britannia at The Last Night of the Proms in 1985. https://www.youtube.com/watch?v=f10I9n-G0Nc Her professional debut in recital was reportedly at the Wigmore Hall, and she has since toured Europe, the Americas, Australia and elsewhere.
In the late 1980s, she collaborated with French & Saunders for their opera diva sketch singing their version of "I Should Be So Lucky" (original by Kylie Minogue) with Sarah as lead.
She appears as Cornelia in the ENO production of Handel's Julius Caesar conducted by Charles Mackerras and directed by John Copley.