Sybil Williams was born on 27 March 1929, in Tylorstown, Mid Glamorgan. She attended the London Academy of Dramatic Arts (now LAMDA), meeting Richard Burton during the filming of The Last Days of Dolwyn (1949). After their marriage, she retired from acting, performing only a few times, and generally on stage rather than on film. The marriage ended famously in 1963, when Burton began a liaison with Elizabeth Taylor. She divorced Burton in 1963 on grounds of “abandonment and cruel and inhumane treatment”, receiving a $1 million settlement and custody of their children.

In 1965, Burton founded a nightclub in Manhattan at 154 East 54th Street, the site of El Morocco; numerous celebrities and well-known artists contributed, including Julie Andrews, Leonard Bernstein, Roddy McDowall, and Stephen Sondheim. “Arthur”, as the club was known, (the precursor to Studio 54) became a popular nightclub for celebrities during its short tenure (1965–69). Frequent habitués included Truman Capote, Wilt Chamberlain, Roger Daltrey, Princess Margaret, Rudolph Nureyev, Lee Remick, Andy Warhol, Angela Lansbury and Tennessee Williams. D.J. Terry Noel claimed to have invented “mixing” in the club, layering music from two separate turntables.

Christopher had two daughters with Richard Burton, Katherine “Kate” Burton (born 10 September 1957) and Jessica Burton (born 1959). In 1965 in Manhattan, New York City she married Jordan Christopher, a singer and actor, and the couple raised his daughter and had another child, Amy Christopher (born May 1967).

Christopher then returned to theatre, founding the New Theatre on 54th Street in New York, and Bay Street Theater in Sag Harbor in 1991.