Saunders was a candidate for mayor of Toronto in the 2023 by-election, where he came in third, to winner Olivia Chow and runner-up Ana Bailão.

[4] He earned an honours bachelor of applied science in justice studies from the University of Guelph-Humber shortly after his appointment as Toronto Chief of Police.

[7] He was selected over Peter Sloly, another black deputy chief who was at that time considered more open to progressive reforms.

[10] The association cited "ineffective leadership, lack of communication skills and failure to take responsibility" as reasons for holding the vote.

[10] At a police board meeting, Saunders stated "I think that we’re all moving in the right direction, are there some communication breakdowns and misunderstandings that need to be identified, absolutely and that’s what we’re going to do.

In the early part of the decade, Toronto police had created Project Houston, a divisional task force which linked the disappearance of three men of South Asian or Middle Eastern origin to Church and Wellesley, Toronto's gay village.

In mid-2017, amid public speculation of a serial killer in Church and Wellesley, evidence was gained from another missing-persons investigation which led TPS to create a second divisional task force, Project Prism.

In October 2023, a Freedom of Information and Protection of Privacy Act request made by NDP MPP Chris Glover, was unable to locate any records of advice, reports, or other work originating from Saunders.

Saunders unsuccessfully contested the 2022 Ontario general election as the Progressive Conservative candidate for the riding of Don Valley West, previously held by former premier Kathleen Wynne since 2003, who was not seeking re-election.

He stated that the family went public about the transplant in order to raise awareness of the organ donation program.

[28][29] Mark's sister Yvonne Saunders is a noted former track and field athlete who competed for Canada at the 1976 Summer Olympics.