Hays attended Western Canada High School, and Strathcona-Tweedsmuir in Calgary, as well as, Appleby College in Oakville. He obtained his B.A. degree in history from the University of Alberta and his LL.B. degree from the University of Toronto. Following his articles, in 1966, with the Calgary-based firm Macleod Dixon, he was called to the Alberta Bar, and became known as a prominent lawyer. Hays was active in various practice areas, most notably corporate, commercial, and international operations. As well, he had a meaningful role in the firm's strategic planning and government relations. He served as Chairman of Macleod Dixon, LLP after his retirement from the Senate. He has been a member of Macleod Dixon, and successor firm Norton Rose Fulbright, for over 50 years.
Hays was appointed to the Senate of Canada by Prime Minister Pierre Trudeau on April 29, 1984, representing Alberta. He chose Calgary as his self-designated senate division. Hays served as Chair of the Senate Standing Committee on Agriculture and Forestry from 1986 to 1988 and again from 1994 to 1995. He was also the chair of the Senate Standing Committee on Energy, the Environment and Natural Resources from 1989 to 1993. He chaired the Committee on Senate Reform, 2006 to 2007. On October 12, 1999, he was appointed Deputy Leader of the Government by Prime Minister Jean Chrétien. Chrétien appointed him as Speaker in January 2001. He is the only Albertan to have held this office.
Hays served as president of the Liberal Party of Canada between 1994 and 1999. He has chaired the party's National Executive Committee and Management Committee, as well as serving as Chair of the Liberal party's Revenue Committee. From 1996 to 1998, he served as Election Readiness Co-Chair and National Platform Co-Chair for the Liberal party. Hays is also the past Chair of the Canada-Japan Inter-Parliamentary Group and the Canadian section of the Asia-Pacific Parliamentary Forum.
On April 29, 2000, Hays received Grand Cordon of the Order of the Sacred Treasure from the Emperor of Japan.[1] He was conferred with this honour for promoting Canada/Japan bilateral relations.
In 2011, Hays became an Officier de la Légion d'honneur for his work in furthering Canada's involvement in the Organisation Internationale de Francophonie.