Steve Mahoney filed his registration Monday to be a candidate for the job being left open by the 93-year-old McCallion, who has announced she won't be running in October's municipal election.
Mahoney, 66, was a Liberal member of the Ontario legislature from 1987 to 1995 and a Liberal MP from 1997 to 2003, when he served as a cabinet minister under then-prime minister Jean Chretien.
He spent time on Mississauga's city council from 1978 to 1987 and also spent several years as chairman of Ontario's Workplace Safety and Insurance Board until 2012.
He's the third person to officially register in the mayor's race so far, but is the most prominent candidate.
McCallion has been Mississauga's mayor for more than 3 1/2 decades since being elected in 1978.
Mahoney says the Oct. 27 election will be pivotal for the city west of Toronto and that he can offer "experienced leadership."
“With Hazel McCallion not seeking re-election, the decisions we make this fall, and for the next four years, will determine the sort of city we pass on to our children,” said Mahoney.
He says he'll officially launch his campaign next month.
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