After an unhappy childhood in Liverpool as one of six children of a Roman Catholic father and a Protestant mother, Jamieson moved to Paris in the 1950s and joined the cast of the cabaret show at the Carousel Theater with the famous French entertainer Coccinelle.
Jamieson had an early sex reassignment procedure in 1960 in Casablanca, Morocco under Dr Georges Burou. She was only the seventh person to receive sex reassignment surgery from Dr. Burou, and the doctor warned Jamieson that the procedure could even result in death, but Jamieson pressed ahead with the operation. Ashley says she bled for weeks after the surgery, and lost large clumps of hair from her head which never grew back.
In her book The First Lady, Ashley tells the shocking story of the rape she endured while still living as a man. A homosexual roommate viciously raped the young George Jamieson, and his anus was severely injured as a result of the sexual assault. Ashley has suffered much psychological trauma as a result.
After returning to England, Ashley became a successful fashion model, appearing in such publications as Vogue and winning a small role in the film The Road to Hong Kong, which starred Bing Crosby and Bob Hope. Her credit, however, was dropped from the film after she was outed as transsexual by the Sunday People in 1961.
She married Hon. Arthur Corbett in 1963, but the marriage did not last. In 1970 Corbett (later 3rd Baron Rowallan) successfully had the marriage annulled on the grounds that Ashley had been born male, which set the precedent for the legal status of transsexuals in the United Kingdom until the UK Gender Recognition Act 2004 came into force.
After a heart attack in London, Ashley retired for some years to the Welsh border town of Hay-on-Wye. Ashley was once great friends with fellow performer and rumoured transsexual, Amanda Lear. According to Ashley's book The First Lady, the two women had a major falling out and haven't spoken in years.
At one time, Catherine Zeta-Jones was rumoured to play Ashley in a film story of her life. Ashley still has many famous friends and fans. She was great friends with the late Doctor Who star Jon Pertwee and his wife Ingeborg. They used to have drinks together in Chelsea.
April Ashley's Odyssey, a biography by Duncan Fallowell, was published in 1982. In 2006, Ashley released her autobiography The First Lady and made TV appearances on Channel Five News, This Morning and BBC News. In one interview, she said, "This is the real story and contains a lot of things I just couldn't say in 1982", including details of her alleged affairs with Michael Hutchence, Peter O'Toole, Omar Sharif, Turner Prize sculptor Grayson Perry and the future 19th Duke of Infantado, among others. However, the book was pulped after it was discovered that it had heavily plagiarized the 1982 book on Ashley Most of the actors mentioned as being lovers of Ashley have denied the truth of these allegations.
- April Ashley's Odyssey by April Ashley with Duncan Fallowell, London: Jonathan Cape, 1982 ISBN 0-224-01849-3
- The First Lady by April Ashley with Douglas Thompson; London: John Blake Publishing Ltd, 2006, ISBN 1-84454-231-9