"I think the best chance for the renewal I want to see in Ontario and in the party, and the person who is better able to get us there than I am, is my friend Kathleen Wynne," Glen Murray said at a Thursday news conference announcing the move.
"And because I believe that renewal is more important than anything else, and because I simply believe she is the best person to be premier of Ontario, she has my full and unqualified support."
The news on Thursday morning comes one day after Murray, the MPP for the Toronto Centre riding, participated in an all-candidates debate and gave no indication he was bowing out of the race. With Murray's departure, there are now six candidates vying for the Liberal leadership — Eric Hoskins, Gerard Kennedy, Sandra Pupatello, Charles Sousa, Harinder Takhar and Wynne.
Wynne is considered one of the frontrunners in the race to succeed outgoing Premier Dalton McGuinty. She said Thursday that Murray would play a senior role in her cabinet if she is elected.
"I know this is a very hard moment for you, because you've put your heart and soul into this, and I'm very grateful that you're coming and we're going to be able to work together," she said, addressing Murray.
The CBC's Mike Crawley reported that Murray's announcement was prompting other leadership candidates to try to bring his supporters to their side, despite his endorsement of Wynne.
Elinor Caplan, a former cabinet minister and MPP, had been supporting Murray, but is now backing Pupatello as the best candidate.
Murray, first elected to the provincial legislature in a byelection in 2010, was the first candidate to formally launch a campaign to become the next leader of the Liberal party.
The Liberals will pick a new leader at a convention later this month to replace McGuinty, who has led the party since 1996.