He served in the Legislative Assembly as a Progressive Conservative from 1975 to 1987, and was a cabinet minister in the governments of Bill Davis and Frank Miller.
[6] After serving as parliamentary assistant to the Attorney General from 1975 to 1977, Grossman was appointed to cabinet on September 21, 1977 as Minister of Consumer and Commercial Relations.
He was widely regarded as the most progressive candidate, and was endorsed by members of the party's Toronto-based Big Blue Machine.
His supporters included Susan Fish, Russ Ramsay, Phil Gillies, Bruce McCaffrey and George Taylor.
Pope was forced on the defensive when one of his workers was caught polling party members as to whether religion would make a difference in the leadership race, which was seen as a reference to Grossman's Jewish background.
[10] Timbrell lost support when he declared his opposition to the full funding of Catholic schools, causing Norm Sterling to defect to Grossman's campaign.
Shortly after winning the leadership of the Ontario Progressive Conservatives, he criticized American "neo-Conservatism" as "a shallow reconstitution of laissez-faire liberalism."
When the Liberals called an early election for the fall of 1987, Grossman's Tories tried to campaign on a right-wing platform of tax cuts and reduced government spending.
Peterson won a strong majority government in the 1987 election, and the Conservatives were reduced from 52 seats to 16, falling to third place behind the NDP—their worst showing in over half a century.
He assisted new party leader Mike Harris in the 1990 provincial election, and coached him to stay "on-message" with the issue of tax cuts.