[2] After graduation, Zirnhelt worked as a civil servant in the federal government of Pierre Trudeau as a member of the cabinet secretariat, and later became the British Columbia head of Opportunities for Youth.

[4] Zirnhelt's first entry into politics was in the 1969 British Columbia general election, where he stood as a candidate for the Liberal Party in the riding of Cariboo.

[4] With the election of a New Democratic government in 1991, Premier Mike Harcourt appointed Zirnhelt minister of economic development, small business and trade.

[7] He was named minister of agriculture, fisheries and food in September 1993,[7] and initially remained in that post when Glen Clark took over as premier from Harcourt in February 1996.

[10] However, he was named minister of aboriginal affairs that November to replace Dale Lovick, who was dropped from the cabinet after declining to run again in the 2001 provincial election.