[4] Raised in Barry, South Wales, she attended a Welsh-speaking comprehensive, Ysgol Gyfun Rhydfelen, before reading drama at Aberystwyth University and subsequently studying at Jesus College, Oxford.
[8] Wiliam joined the BBC Radio's Light Entertainment department in 1988,[9] but left in 1991 to produce the live television show Tonight With Jonathan Ross broadcast by Channel 4, remaining with the programme for a year.
[10] She left her post at ITV in January 2006 following decisions made by Simon Shaps, director of television, about management restructuring.
Wiliam rejoined the BBC in March 2015 to commission Radio 4's comedy output and works for the network on three days each week.
[12][3] Wiliam is married to Ian Brown, known for his scripts for the My Family sitcom; the couple have a son.