A schoolteacher, Quill was first elected to Dáil Éireann for the Cork North–Central constituency at the 1987 general election. She was one of 14 Progressive Democrat TDs the first election after the party was founded. She had previously contested the 1977 and 1981 general elections as a Fianna Fáil candidate.
She retained her seat in two successive general elections, but lost it at the 1997 general election to Billy Kelleher of Fianna Fáil. She was then nominated by the Taoiseach, Bertie Ahern, to the 21st Seanad. She did not contest the 2002 elections.