The party was founded by Marc-Boris St-Maurice, an activist and member of the punk group Grim Skunk. After a 1991 arrest for possession of marijuana, he vowed to legalize cannabis. He started by creating the Bloc pot, a Quebec political party and eventually, as the current law prohibiting the possession of cannabis is a federal law, founded the federal Marijuana Party. On February 28, 2005, St-Maurice announced his intention to join the Liberal Party in order to work for liberalized marijuana laws from within the governing party.
Blair T. Longley became the new Party Leader following St-Maurice’s resignation.
In the 2000 federal elections, the party nominated candidates in 73 ridings in 7 provinces and won 66,000 votes (0.52% of national total). It nominated 71 candidates for the 2004 general election and won 33,590 votes (0.3%). The decline may be at least partly due to the fact that the Liberal Party of Canada, the Bloc Québécois (Bloc) and the New Democratic Party (NDP) have been moving towards decriminalization of the drug.
Some party members were said to be considering endorsing the NDP because of its liberal stand on marijuana laws during the last campaign. However, the party has attracted new members from the NDP ranks as their commitment to ending cannabis prohibition has been lukewarm at best, and at times the party has been actively hostile toward activists who promote this policy. One example is cannabis activist Tim Meehan, the Marijuana Party candidate for Ottawa South, who worked on the NDP campaign in the 38th General Election.