[3] She is the daughter of Eleanor Lynne (Conway) and Kelburne "Kit" McNabb Leitch, who owned a construction company in Fort McMurray.

In 2009, Leitch founded the Kids Health Foundation (now known as The Sandbox Project), an organization that sought to work with academia, the not-for-profit sector, government and industry to make Canada the healthiest place on earth for children to grow up.

The Globe described Leitch as a "star candidate" and noted that her launch event in Creemore the following day would include former Ontario premier Bill Davis and federal Finance Minister Jim Flaherty.

[14] Leitch won the nomination over Collingwood mayor Chris Carrier and Paul Throop with 67% of all ballots cast in a large turnout.

[17] On October 2, 2015, during the general election, Leitch and then-Minister of Citizenship and Immigration Chris Alexander announced a Royal Canadian Mounted Police "tip line" where Canadians could report "barbaric cultural practices", which, along with the niqab issue, was widely viewed as an attempt to keep cultural and immigration issues at the forefront of the election campaign.

[20] However, in an interview, on the statement the tip line "is a good idea but wasn't communicated as effectively as it could be to the public" she characterised it as being "absolutely correct".

[24] She recruited Nick Kouvalis and Richard Ciano to head her leadership campaign,[25] and Andy Pringle of the Toronto Police Services Board was her chief fundraiser.

In a September interview with the Canadian Press, Leitch made the following statement in response to the backlash she had been receiving: "I don't think it's intolerant to believe in a set of values that we expect everyone to share here and include those people who are coming to visit or immigrate to Canada.

"[29] The focus of her campaign around the policies surprised some of her long-time mentors, such as former Conservative senator Hugh Segal, who couldn't support her leadership bid.

[31] Stephen Maher, based on information he received from former staffers of Letich, argued that her campaign manager Nick Kouvalis, thought that it would give Leitch, a way to win.

[32] In a November 9, 2016 interview with Toronto Life magazine, Leitch cited the belief that gays should not be sentenced to death as an example of one such Canadian value.

In December 2017, it was reported that Essa Township mayor Terry Dowdall and physician Gillian Yeates were challenging Leitch for the Conservative nomination in Simcoe—Grey for the next election.

[27] Leitch threw her support towards Marc Biss and Tim Bulmer, to be the party candidate for her riding arguing that they were "real conservatives" while believing Yeates and Dowdall were not.