For a man who became one of Ontario's most successful premiers, Dalton McGuinty never seemed to be destined for the history books.

When he first arrived at the Ontario legislature in 1990 as a Liberal MP, few took much notice of the lanky lawyer swimming in an ill-fitting double-breasted suit, much less peg him as a future leader of the province.

Yet over the years, McGuinty managed to beat the odds again and again, from his unlikely leadership victory in 1996 to winning his third consecutive election last year — a feat unmatched by his party since Sir Oliver Mowat more than a century ago.

Along the way, he crafted a political style that saw the Liberals through many of the obstacles they faced over the last nine years.

"Never too high, never too low" are the words McGuinty lives by, an extension of his straight-laced, father-knows-best image.

Unexpected resignation

But the man dubbed "Premier Dad" decided to cash in his chips Monday, stepping down amid a series of scandals that seemed insurmountable, even for him.

He'd alienated a powerful ally — Ontario's teachers — by forcing a pay freeze to reduce the province's massive $14.4-billion deficit. Public sector unions declared war, vowing to withdraw their financial support and use their organizational might to defeat McGuinty in the next election.

They made good on their threat in a Sept. 6 byelection McGuinty orchestrated to gain the one seat he needed to regain a majority government, putting boots on the ground to elect a New Democrat for the first time in the riding's history.

Adding to McGuinty's troubles were a rare contempt motion over the costs of cancelling two gas plants in Liberal ridings and a growing scandal over the province's Ornge air ambulance service, which is under a criminal probe.

By tendering his resignation and shutting down the legislature, McGuinty bought time for his party to elect a new leader, mend its relationship with the unions and wipe the slate clean on the contempt motion.

But McGuinty bristled Monday at the suggestion that he saw the writing on the wall and was getting out while he could.

Three terms as premier

Throughout his political career, people have told him that it couldn't be done — that he couldn't win a seat as a Liberal, that he couldn't win the leadership, that he couldn't win the election. 

mi-300-mcguinty-cp674501

Dalton McGuinty was first elected as Ontario premier in October 2003. He announced his resignation on Monday night, nine years later. (Tobin Grimshaw/Canadian Press)

"In 2003, in 2007, in 2011, we went into each of those elections behind," McGuinty said.

"So of course there's still going to be a few people out there who are going to say, you can't win. It has nothing to do with that."   

Growing up in Ottawa as the eldest son in a large Catholic family, McGuinty helped his busy parents care for his nine younger siblings. He worked odd jobs though high school to help out, from hospital orderly to a counsellor at his father's summer camp.

As premier, McGuinty would often draw from his childhood to impart a political lesson about the responsibilities of leadership. Sometimes they'd take a humorous turn to his no-nonsense mother Elizabeth, a nurse, whose tough love kept his ego in check.

Life before politics

He studied science before turning to law. In 1980, he married his high-school sweetheart Terri, an elementary school teacher. Together, they had four children: Carleen, Dalton Jr., Liam and Connor.

McGuinty jumped into politics in 1990 under tragic circumstances.

His father Dalton Sr., an English professor and provincial politician, died suddenly while shovelling snow and his eldest son was recruited to succeed him in Ottawa South.

McGuinty often joked that he was selected because the election signs already had his name on them.

He won the seat, bucking a New Democrat tide that washed the Liberals out of office.

Despite his bland public persona, McGuinty managed to squeak out an upset victory in the 1996 Liberal leadership race after placing fourth in the first two ballots.

He spent the next seven years in Opposition, failing to lead the Liberals to victory in the 1999 election with the Tories branding him as not ready for prime time.

"I think he was an accidental party leader, he only got 17 per cent of the vote in the leadership convention that elected him, like Stephane Dion," said Nelson Wiseman, a politics professor at the University of Toronto.

"When I saw him in 1999, I thought, you know, looks like the Conservatives are right. This guy isn't ready to be premier."

But McGuinty rallied after some media grooming — by the same Chicago consulting firm that helped Barack Obama win the U.S. presidency — and rejigging of the party machinery.

He beat the beleaguered Tories in 2003, who were dragged down by a series of scandals over the fatal shooting of an aboriginal protester, tainted water and a massive blackout.

Challenges as premier

His credibility took a hit shortly after he first became premier when he imposed a health-care premium of up to $900 per worker, despite signing a pledge during the campaign not to raise taxes. He insisted he had no choice as the Tories for leaving a hidden $5.6 million deficit.

He did another flip flop on taxes in 2009 when Ontario was teetering on the brink of the global recession, combining the provincial sales tax with the federal goods and services tax after campaigning against the idea for years.

Both showed that behind McGuinty's paternal image was a shrewd politician who was prepared to make unpopular decisions if he thought it was the right thing to do.

mi-300-mcguinty-caucus-cp0254794

With Ontario Premier Dalton McGuinty's pending departure as Liberal leader, his party will have to call a leadership convention to determine his successor. (Nathan Denette/Canadian Press)

The Liberals were beaten down by other scandals involving grants to ethnic groups and a so-called "billion dollar boondoggle" at eHealth Ontario, both of which cost cabinet ministers their jobs.

But McGuinty always bounced back.

He easily led the Liberals to a second straight majority in 2007 when then-PC leader John Tory made the unpopular promise of extending public funding to religious schools, effectively handing McGuinty the election victory.

The self-described "education premier" poured money into health care and education, more than doubling government spending and the province's debt while racking up record deficits after the recession hit.

However, it wasn't until this year's scandal at the Ornge air ambulance service and the political decisions to cancel the two plants that things started sticking to the "Teflon premier."   

Taxpayers are on the hook for hundreds of millions of dollars for cancelling the gas plants and McGuinty seemed to recognize this time the public anger was being directed at him.

"To keep that kind of reputation as he's kept over the years I think is tough," said NDP Leader Andrea Horwath.

"But he was able to keep a very positive reign in government for a number of years, and I think that's something he probably should be very proud of. Maybe not so much the last little while, but certainly for several years prior to that."

McGuinty said he will stay on as the MPP for Ottawa-South until the next election, but wouldn't comment on speculation he's considering a run for the leadership of the federal Liberals.

"I am not making any plans whatsoever beyond my duties here at Queen's Park," he said.

Asked what advice he would give his successor, McGuinty was curt.   

"Don't screw it up."