George Smitherman is the mayor Toronto could have had: an openly gay liberal who overcame an admitted history of drug use to become Ontario's deputy premier. Instead, Canada's largest city got Rob Ford, whose erratic behavior and confessed crack cocaine and alcohol use while in office have embarrassed his fellow citizens and delighted America's late-night TV comedians, leading the city council to strip him of most of his powers this week.

If Toronto is a tale of two cities, the 49-year-old Smitherman represents the one better known to the world – the mainly liberal downtown of Canada's financial capital. Ford hails from the city's vast conservative suburbs, where he won over voters with promises to stop "the gravy train" of government spending and end a so-called "war on cars".

Smitherman, a polished politician, openly told voters during the 2010 campaign that in the 1990s he had beaten a five-year addiction to unspecified "party drugs". Ford attacked his opponent on those and other grounds, and won.

Now Ford's own drug history is emerging for the world to see. It turns out Toronto elected a mayor who admitted to smoking crack in the past year during one of his "drunken stupors", insists he is not an addict and refuses to resign or take a leave of absence. Many in the city are shocked. Ford's former opponent is not.

"For anyone who cared to look, all of the mayor's limitations and issues were there from the beginning, before he started campaigning, so I'm not surprised by what's happening at City Hall and with him, just deeply saddened by it all," Smitherman said in an interview from the downtown home that he shares with his husband and two young, adopted children. "He took some dirty shots at me, attacking my sexuality and track record, throwing his weight around to be heard above anyone else. Not much has changed."

A collective cry of disbelief rang out from Toronto's urbanites on 25 October 2010, at the news that the rightwing, larger-than-life, unscripted Ford had defeated the more moderate, green energy-loving Smitherman for mayor of the traditionally centrist city. The suburbs had spoken.

Toronto's politics had begun a dramatic shift in the late 1990s, when the city annexed the suburbs and suddenly gained massive numbers of conservative voters who grew resentful of rising taxes and liberal downtown initiatives like expanded arts and culture projects and bike lanes. The 2010 election for mayor wasn't pretty. The Ford campaign questioned whether Smitherman's past drug use made him unfit for office, though Ford had been charged with marijuana possession and drinking and driving in 1999.

Smitherman didn't heavily attack Ford's past on those grounds.

"I campaigned honorably," Smitherman said. "I'm not a person prone to regret, but I'm reminded of that old adage, 'Don't bring a knife to a gun fight.' I think we were not aggressive enough in exposing his weaknesses that are even more apparent now."

Ford also cast himself as a traditional family man, contrasting his wife with Smitherman's husband – though Ford had been charged with domestic assault in 2008. Voters saw Smitherman's sexuality as a negative, said University of Toronto political science professor Nelson Wiseman.

"People knew they were electing a mayor with warts … but Smitherman being gay didn't help him in that election," Wiseman said.

Ford also appealed to the city's conservatives by painting Smitherman as a tool of Toronto's liberal elite and himself as an authentic everyman. The election wasn't really close: Ford defeated Smitherman by a margin of 47% to 36%. And Ford's core of conservative supporters, known as "Ford Nation", was born.

"It was a Tea Party kind of time in Toronto," Smitherman said. "That election was similar to when the Tea Party was at its heights in the US and the guy that never spent a penny was more authentic than the guy who spent $250m. Experience became a negative rather than a positive. I ended up as the de facto incumbent in the race where incumbency was unhelpful."

Smitherman entered the 2010 mayoral race after years as a member of Parliament for the provincial Liberal Party, where he served as health minister and deputy premier and went on to become then-premier Dalton McGuinty's righthand man. That experience was marked by criticism over hundreds of millions of dollars in spending on an electronic health records system, and Toronto's suburban voters were wary of what Smitherman might do in charge.

"Ford's simple and populist message meant it rang very well in the suburbs," Smitherman said. He also attributed his loss to Toronto's political system, where political parties are largely absent. The 2010 mayoral race had about 40 candidates, and Smitherman said he took part in 106 debates. None of those debates was head-to-head with Ford.

George Smitherman received 36% of the vote in the 2010 election for mayor of Toronto. Photograph: Frank Gunn/AP

Smitherman could have campaigned differently or attacked Ford's past, but "I'm not sure that would have won over people in Ford Nation," Wiseman, the professor, said. "He's not in touch with the suburbs. He's someone like myself who lives downtown and has a downtown sensibility. Walks to a lot of things, thinks subways are good, who wants to wage a war on the car. Someone coming from the suburbs will always beat someone coming from the city because of demographics.

"The old city of Toronto has about 750,000 people, the suburbs have two million. Do the math."

Smitherman has moved from politics into a private-sector job as a consultant for startup companies. He says he has moved on from his loss in the mayoral race, no matter what Ford does. "I loved politics," he said. "but on the other hand, losing opens up pathways that are extraordinary. I stand at this point in my life, months away from my 50th birthday, without regrets and a pretty exciting road that I'm on."