Hennessy was a member of the
Fort William city council from 1962 to 1969, and served on the
Thunder Bay City Council for seven years after amalgamation. He was first elected to the Ontario legislature in the
1977 provincial election, defeating
New Democratic Party candidate
Iain Angus by 2,256 votes in
Fort William. Hennessy was re-elected without difficulty in the provincial elections of
1981, and
1985. He served as a
backbench supporter of the
Bill Davis and
Frank Miller administrations. He lost his provincial seat in the
1987 election, falling to
Liberal Lyn McLeod by 1,463 votes. Hennessy campaigned for re-election to the
Thunder Bay City Council in 1988, and won more votes than any other candidate. He died in 1991, less than twenty-four hours after attending his last council meeting. The legislature paid tribute to Hennessy on March 18, 1991.
Mike Harris, then leader of the Progressive Conservative Party, credited Hennessy with bringing "a touch of the common person back to the caucus discussions". ==References==