[2] As a member of Parliament, he was known for his work in successfully banning conversion therapy in Canada, adding transgender, gender identity & gender expression to both the Canadian Human Rights Code and hate crimes section of the criminal code, eliminating criminal records for simple possession of drugs, and ending the ban on gay & bisexual men from donating blood.

[3][4][5][6][7][8] A former criminology and political science instructor at Camosun College, Garrison is openly gay and married to Teddy Pardede.

[13] By the 1990s, and until he was elected as a member of Parliament, he taught at Camosun College, in criminal justice, political science, and Pacific Rim studies.

[14] At the time, he was president of the Vic West Community Association and executive director of the South Pacific People's Foundation of Canada.

[15][16] Garrison's other work overseas included peace-building between religious groups in Indonesia and investigating human rights issues in Afghanistan.

During the 2012 New Democratic Party leadership election, following the death of Jack Layton, Garrison supported Peggy Nash, saying she "embodies the NDP values of social justice, environmental sustainability and prosperity for all".

[20] Following the election, fellow British Columbian NDP MP Jean Crowder was appointed his political mentor.

[23] Garrison also successfully fought the attempted deportation of a constituent through a public campaign to the Minister of Citizenship and Immigration Jason Kenney.

Garrison also introduced a motion (M-460) to implement an action plan via the federal government to save the remaining Southern resident killer whales.

Party leader Thomas Mulcair appointed Garrison to be the critic for national defence and LGBT issues.

[43] This bill would have added members of the lesbian, gay, bisexual, transgender, queer and two-spirit communities to the Employment Equity Act,[44] requiring the government to keep track of and set targets for the representation of these groups within the federal public service.

[2] During this Parliament, Garrison played a critical part in the debate and passage of Bill C-4, which banned the practice of conversion therapy in Canada.

A year-and-a-half later, with another federal election expected soon, Garrison was acclaimed the NDP candidate,[56] and again faced Martin, but this time the Conservative challenger was lawyer Troy DeSouza.

This January 2006 election was again considered a toss-up and as a result CBC Radio One's Cross Country Checkup broadcast a show highlighting the riding and the candidates.

[60] Instead, Garrison stood in the November 2008 local government election where he won a seat on the Esquimalt municipal council.

[61] The council adopted a resolution, proposed by Garrison to fund the full budget requests of the police minus one dollar.

[62] Garrison advocated for stricter targets of greenhouse gas emissions reduction,[63] and passed a motion supporting a permanent ban on coastal drilling and tanker traffic in BC waters.