Whitrow was born in Oxford, the son of Mary Alexandra (Flaunders) and Philip Whitrow. He attended the Dragon School, Tonbridge School, and the Royal Academy of Dramatic Art. He served in the King's Dragoon Guards during his national Service from 1956 to 1958. He joined the Royal Shakespeare Company in 1981. He played Russell in the original radio version of After Henry by Simon Brett.
Whitrow was married to Catherine Cook, with whom he had two children: Hannah Mary Whitrow (b. 1973) and Thomas George Whitrow (b. 1976). He also had a son, Angus Imrie (b. 1994) with Actress Celia Imrie.
In 1989, Whitrow appeared in episode four of the BBC Two Sketch show A Bit of Fry and Laurie (series one), playing an irate member of the audience who claimed that Stephen Fry and Hugh Laurie had stolen several of their sketches from him.
Between 1990 and 1992, Whitrow appeared in the sitcom The New Statesman as Paddy O'Rourke, a Labour Shadow minister who feigned an Irish accent when in public to attract the working-class vote.
In the year 2000, in the successful animated movie Chicken Run, Whitrow voiced the character of Fowler; an old rooster who claims to have fought in World War II.
Whitrow's last work was two plays for BBC Radio 4 where he played the late Poet Laureate, Sir John Betjeman. Mr Betjeman's Class was his last completed work. Whitrow died while recording Mr Betjeman Regrets and was completed by Robert Bathurst. Both plays were broadcast on BBC Radio 4 during Christmas 2017.
