TORONTO -- The latest contender to jump into the race to replace Premier Dalton McGuinty is no stranger to war zones, but he plans to play peacemaker.

Former cabinet minister Eric Hoskins said he wants to help the embattled Liberals get back on track, after coming under fire over the costly cancellation of two gas plants and a criminal probe into the Ornge air ambulance service.

The government has made a lot of progress, but it must acknowledge that it's made a few mistakes along the way, he said Tuesday in launching his leadership bid.

"For if we as a party cannot be honest with ourselves about the work that must be done, about what we have gotten right and about what we have gotten wrong, then we cannot be honest with Ontarians," Hoskins told a roomful of supporters, including MPP Tracy MacCharles, who represents Pickering-Scarborough East.

The decision to cancel the plants in Oakville and Mississauga, which will cost taxpayers at least $230 million, should have been made "much earlier on in the process," he told reporters.

"We have to acknowledge what has happened in the past and the difficult decisions that were taken," he said.

If he becomes premier, both rural and urban communities will have an equal say in future plans for wind farms or power plants, but it will also have to be balanced against the "legitimate energy needs" of the province, Hoskins said.

His parents, who live in southwestern Ontario, have given him an "earful" about wind farms, he said.

The issue has riled some rural communities who complain that the minority Liberals are ignoring their opposition to wind turbines to satisfy residents in the Greater Toronto Area.

It's no surprise that some candidates are trying to position themselves as leaders who could win seats in rural communities, said Peter Graefe, politics professor at Hamilton's McMaster University.

"In the last election, what kept them from the majority was losing seats outside of the GTA," he said. "And we can think of the eight seats down in southwest Ontario, stretching up to Lake Huron."

The Toronto candidates can say they will firm up Liberal support in the GTA, but they also need to show that they can push the party into majority territory, Graefe said.

Hoskins, 51, insisted Tuesday that he's not just a big-city guy, even though he represents the Toronto riding of St. Paul's and has lived in the city for years.

He emphasized his rural roots in Simcoe -- where he was born and raised -- and his work in northern Ontario as an emergency room and family doctor.

Hoskins is perhaps more well-known outside political circles as a celebrated humanitarian who started War Child Canada with his wife, Dr. Samatha Nutt. Both of them practice medicine and have a seven-year-old son, Rhys.

Running a multimillion-dollar international charity also taught him how to work with a tight budget, he said.

The Oxford-educated Rhodes scholar is an Officer of the Order of Canada and received the United Nations Lester B. Pearson Peace Medal, as well as the Governor General's Meritorious Service Cross.

Hoskins was a senior adviser to former foreign minister Lloyd Axworthy on issues such as human rights, child soldiers, peacekeeping and the ban on landmines.

But he also has some star power, having rubbed elbows with celebrities and musicians through his work with War Child.

Canadian rapper K'Naan endorsed his friend on Twitter, asking people to join the party to vote for Hoskins.

"Good news 4 those who want humanity in politics," he tweeted.

The work he'd done outside politics is what makes him different from the other candidates, Hoskins said.

"Politics offers one perspective on the work that must be done," he said. "But life outside of politics, grounded in diverse experience, offers another."

During their work in war-torn countries, Nutt said she and her husband were ambushed and once came under fire. It was in those life-or-death moments that she saw what he was really made of, she said.

His "boundless compassion," his "deep concern for those around him," his courage and ability to think rationally in times of crisis, said Nutt.

"And most of all, you could see his innate ability to lead," she said.

Hoskins was first elected in a 2009 byelection that was triggered when former cabinet minister Michael Bryant left politics, and was soon elevated to cabinet as minister of citizenship and immigration.

He resigned as minister of children and youth services last week -- a prerequisite set by McGuinty for making a leadership bid.

He joins Gerard Kennedy, Sandra Pupatello, Charles Sousa, Glen Murray and Kathleen Wynne in the leadership race.

Kennedy has taken aim at McGuinty's move to prorogue the Ontario legislature on Oct. 15, promising to recall members "as soon as possible" if he becomes leader. Murray and Hoskins have made the same promise.

Pupatello, however, said she would wait until she has a seat in the legislature before recalling the house.

Hoskins, like Wynne and Pupatello, also said he believes the government won't need proposed legislation to freeze the wages of public-sector workers, because they'll be able to reach agreements through negotiation.

Potential Liberal leaders have until Nov. 23 to launch their bids and sign up new members who will vote for delegates to be sent to the Toronto convention at the end of January.