Mazankowski was born in Viking, Alberta to parents of Polish decent. He went into business becoming the manager of an auto-dealership. Long interested in politics Mazankowski became an important member of the Albertan Progressive Conservatives and in 1968 was elected to the Canadian parliament.
During the briefly lived Clark government Mazankowski served as Minister of Transport. When the Tories returned to power under Mulroney in 1984 Mazankowski again became Minister of Transport. In 1986 he was promoted becoming Deputy Prime Minister and Government House Leader. Mazankowski became one of the most widely known public faces of the Tory government. He played an especially important role as an advocate for the Canadian-American Free Trade Agreement and NAFTA.
The Mulroney government became increasingly unpopular, however, but Mazankowski was less severely affected than others. In 1991 he became Fiance Minister replacing the extremely unpopular Michael Wilson. A position which he retained under Kim Campbell.
Mazankowski retired from politics on June 7, 1993 not running in the 1993 election that saw his party reduced to two seats in the House of Commons. He left for the private sector, serving on corporate boards. He has still remained closely involved in politics. In 2002 he headed an investigation in Alberta's health care system. Recently he has played an important role in the merger between the Progressive Conservatives and the Canadian Alliance party and is a strong supporter of the new Conservative Party of Canada.