Receiving his high school diploma from McLaughlin Collegiate and Vocational Institute in Oshawa, Ontario, Siksay attended Victoria College at the University of Toronto, graduating with a BA in 1978.

He then enrolled in the MDiv programme at the Vancouver School of Theology at the University of British Columbia, studying as a candidate to be a congregational minister in the United Church of Canada.

In May 2005, Siksay introduced a bill to amend the Canadian Human Rights Act to prohibit discrimination on the basis of gender identity or expression.

By June 2010, the private member's bill (C-389) had proceeded to the Standing Committee on Justice and Human Rights, with little overt opposition from the Conservative Party of Canada minority government evident.

On July 2, 2014, Siksay began as working as the administrative assistant to the bishop of the Anglican Diocese of New Westminster, Melissa M. Skelton, who retired February 28, 2021.