She is best known for her performances in three of Mike Leigh's films – Another Year and Happy-Go-Lucky and Mr. Turner.
Fernandez began her regular theatre work in 1997, and has since performed in several plays including Shopping and Fucking and Woody Allen's Murder Mysteries.
[2] She has appeared regularly on British television, including appearances in Twenty Twelve, My Family, The Forsyte Saga,[3] Married Single Other and Killing Eve.
Her first major film was the multiple award-winning Happy-Go-Lucky, directed by Mike Leigh, where she played a flamenco teacher from Seville with emotional problems.
Fernandez has narrated two audio books – The Happy Home for Broken Hearts by Rowan Coleman, and Want to Know a Secret?