She portrayed forensic pathologist Dr. Laura Hobson in the crime drama series Inspector Morse and its spin-off Lewis from 1995 to 2015.
Holman started her acting career in the 1988 television film The Rainbow based on the novel by D.H. Lawrence, directed by Stuart Burge.
Holman was nominated for a 1997 Laurence Olivier Theatre Award for Best Actress in a Supporting Role in 1996 for her performance in Who's Afraid of Virginia Woolf?.
In 2007, Holman played Wendy the narrator and mother of Michael in the television series Fallen Angel, a story about Rosie Byfield, a clergyman's daughter who grows up to be a psychopathic killer, starring Emilia Fox.
From April to May 2015, she appeared as Myra Bolton in Doris Lessing's play, Each His Own Wilderness, at the Orange Tree Theatre in Richmond, London.