Born in Montreal, Quebec, Lynch-Staunton was educated at Collège Stanislas and Collège Jean-de-Brébeuf in Montreal. He then obtained a B.Sc. from Georgetown University in Washington, D.C in 1953, and a History degree from Queen's University in Kingston, Ontario before pursuing a career in business.
He was appointed to the Senate by Brian Mulroney on September 23, 1990, representing the Senatorial Division of Grandville. The following year, he was appointed Deputy Leader of the Government in the Senate, and became Leader of the Opposition in the Senate in December, 1993 following the Liberal victory in that year's general election.
On December 8, 2003, with the merger of the Canadian Alliance and the Progressive Conservative Party of Canada ratified by both parties, Lynch-Staunton was appointed interim leader of the new Conservative Party of Canada until a formal leadership race can be held in March 2004.
He has been married to Juliana deKuyper since 1958, and has five children.