Caccia was born in 1930 in Milan, Italy. A professor of forestry at the University of Toronto. He was a co-founder of COSTI in Toronto. Caccia's first wife, Mildred, was a candidate for the Ontario Liberal Party in a provincial election in the 1970s. They had two children, Nicolette and John, and were divorced. Caccia was survived by second wife Iva.
Caccia was best known for his strong pro-environment views on the left of the Liberal party. He served at various times during the ministries of Pierre Trudeau and John Turner as Minister of Labour, Minister of the Environment, Parliamentary Secretary to the Solicitor General of Canada, Parliamentary Secretary to the President of the Treasury Board, and Parliamentary Secretary to the Minister of Manpower and Immigration. He most recently was the Chair of the Standing Committee on Environment and Sustainable Development, and of the subcommittee on Agenda and Procedure of the Standing Committee on Environment and Sustainable Development. He was the Liberals' Environment critic from 1984 to 1989, and spent most of the rest of his career on the backbench.
One of the most left-leaning Liberal Members of Parliament (MPs) known for his stance on environmental issues and his staunch opposition to the 2003 invasion of Iraq, he was one of the few Liberal MPs to back Sheila Copps in the Liberal Party's 2003 leadership election. His left-leaning politics and support of Copps ended his political career when the more right-leaning Paul Martin became Liberal leader and prime minister in 2004. Martin backed former Toronto city councillor Mario Silva for the Liberal Party nomination in Davenport. With Martin's support, Silva signed up enough new members until it was obvious he would defeat Caccia for the nomination. Caccia pulled out of the race, and after some talk, chose to retire from politics rather than run as an independent or Green in the 2004 election.
In 1964, he was labelled as a communist by East York Mayor True Davidson for suggesting that Toronto city run day cares accept children from mothers in two parent working families. At the time they only accepted children from single working mothers.
1Until 1909, the office of the minister of Labour was a secondary function of the Postmaster-General of Canada. W. L. M. King was the first to hold the office independently.
2The office of Minister of Employment and Immigration, and Minister of Labour were abolished and the office of Minister of Human Resources Development went in force on July 12, 1996. Under the new provisions, a Minister of Labour may be appointed. However, when no Minister of Labour is appointed, the Minister of Human Resources Development shall exercise the powers and perform the duties and functions of the Minister of Labour.