When Olivia Chow and Jack Layton were married on the Toronto Islands in 1988, they gave themselves a tandem bicycle as a wedding present. He always rode in front and she in back – much as they did in life. He was the orator, she was the organizer; together they were a formidable political couple on Toronto City Council, in the NDP and on the opposition benches in the House of Commons. Since Mr. Layton's death in 2011, three months after he led the NDP to its largest electoral success ever, the bike has been stored in the basement of their Victorian semi on Huron Street, and Ms. Chow has been riding solo as NDP transportation critic in Ottawa, and now as a front-runner in the mayoral race to wrest the chain of office from Rob Ford.

The campaign is partly a homecoming, partly a tribute to her decades of political and social activism and partly a gamble that Ms. Chow, 57, who was the supporting player in a duo with a charismatic public face, can move into leadership mode and unite the disparate parts of the country's most diverse and polarized city.

Ms. Chow launched her campaign with the slogan 'New Mayor, New City' less than three weeks ago. Wearing a black dress and a jacket the colour of daffodils, she stood confidently in front of a bank of cameras and delivered a sleek performance in a packed church hall on the fringes of the St. James Town neighbourhood where she grew up, an only child, caught between a raging, physically abusive father and a fiery tempered mother. Her tightly scripted speech emphasized her four key messages: putting children at the heart of the city; growing the economy; fixing transit and minding the public purse. Since then her team has released an impressive barrage of updates and statements on social and every other kind of media. Off camera, off teleprompter, she is less impressive.

Story continues below advertisement

In the burgundy living room of the home she and Mr. Layton bought 20 years ago on the edge of Kensington Market, Ms. Chow talks about her politics and her life. She speaks in brief bursts, rather than expansive paragraphs. "If there had been a really good mayor and we could be proud of what the city is doing, then my decision might have been different," Ms. Chow says. "But there seems to be a huge vacuum."

Her strength lies not in persuasive intellectual arguments, but in collective action. She is what used to be called "a doer," a person who brings people together on a committee to organize after-school programs or to expand the languages that can be served on 911 emergency calls. 'Doers' don't make late night talk shows or viral YouTube videos, but they resonate with ordinary folks and community activists such as family doctor Joseph Wong, founder of the Yee Hong Centre for Geriatric Care. Mr. Wong, also an immigrant, met Ms. Chow in the late 1970s when she was working on behalf of Vietnamese boat people.

He says Ms. Chow has "integrity and honesty," she can bring people together at city council and restore the pride and credibility we have lost.

She has a poignant narrative, decades of social activism and a strong team behind her. But Ms. Chow has a challenge ahead to parlay that into a galvanizing vision that will overcome Rob Ford's powerful, if simplistic, "stop the gravy train" semantics, and unravel John Tory's verbose bromides about moving the city neither "to the left nor the right, but forward." In the first televised debate this week, Ms. Chow was scrappy, but she couldn't topple Mr. Ford from his bully pulpit, or silence Mr. Tory's insistence that she is the NDP candidate.

Both Mr. Ford and Mr. Tory have denounced her as a "tax and spend" socialist, although neither has provided any examples. "That's because there is no evidence," says Councillor Joe Mihevc, a Chow supporter, who remembers her as "tough as nails" when she sat on mayor Mel Lastman's budget committee, especially when it came to drilling deep into budget lines to find funds to reallocate to community programs such as school nutrition. "It is the politics of deception and repetition," Mr. Mihevc says about the NDP slurs, "until people think that it is true."

Councillor David Shiner, who was Mr. Lastman's budget chief, tells a different tale that reflects the perception she must overcome. "Olivia often wished to expand social service programs at the cost of the taxpayer," he recalled. "It was something that we had to manage and control at the budget committee to make sure that we didn't increase taxes beyond what property taxpayers could afford to pay."

Ms. Chow has heart and experience, but whether she has the rhetorical passion to cut through the verbal sparring and connect with voters outside her left-of-centre base is another question. If she is to make history as the first Chinese-born mayor of Canada's largest city, being a 'doer' may not be enough.

Story continues below advertisement

Three days after the downtown launch, the Chow team holds a rally at the Prince Hotel in North York, the gateway to the suburbs.

Why? "To show we could," says veteran campaign manager John Laschinger – he earlier ran campaigns for June Rowlands (winning), David Miller (winning) and Joe Pantalone (losing). At a time on Sunday morning when lots of people still have their heads under a pillow, volunteers have exhausted their supply of campaign buttons and hotel guests are gawking over their brunch menus at the rainbow parade of students, parents with babies, activists trading campaign tales and seniors pushing walkers to an already crowded ballroom.

Patricia Hinds, a white-haired senior, confides she is embarrassed to say she is from Ford Nation in Etobicoke. She is here because she believes in Ms. Chow's "compassion, skill and vision."

Filmmaker Deepa Mehta has a similar tale, telling the crowd how, as a recently arrived immigrant in the 1970s, she put her daughter Devyani Saltzman into the daycare at St. Stephen's Community Centre, where Ms. Chow was on the board. "I remember her personality … forceful yet friendly," Ms. Mehta recalled in an e-mail, explaining how she has watched Ms. Chow "navigate" the corridors of power. "People tend to focus on your race, your story, your narrative and, important as this may be, it is the work that tells the story."

Orange has disappeared from the colour spectrum and references to Mr. Layton and the NDP are few in Ms. Chow's slick, professional campaign that has been building momentum for nearly two years. The earliest manifestation was the publication of her memoir, My Journey. Even while she was irritatingly coy about her electoral ambitions, she used her national book tour to deliver her primary narrative: I am an immigrant; my mother worked in a hotel laundry; I learned to count every penny.

No other candidate can top that tale, so they have largely ignored it. Instead they go after her bold transit strategy: Ms. Chow wants to trash the Scarborough subway extension and replace it with the discarded blueprints for the light-rail transit system that goes back to the days of David Miller.

Story continues below advertisement

The LRT would be built more quickly and cheaply, and Ms. Chow points out it would have more stops and encourage commercial development in the areas around the stops. Calgary's Naheed Nenshi, the most popular mayor in the country, sees the logic behind that. At a speech at the Toronto Board of Trade late last month, he professed to be baffled by Toronto's decision to build a $3.5-billion subway in Scarborough instead of a light-rail transit line. "I don't understand why you'd not spend less to move more people," he said.

Ask her bluntly: How are you going to save money for taxpayers? And she retorts: "the Scarborough subway is a billion bucks." Before she made a final decision to run for mayor, she says she had a look at the capital budget for the planned Scarborough subway extensions. "And I thought: 'Wow. With those borrowing costs, we are going to spend a lot of money just paying interest. There is hardly anything left.'"

What about the agreement with feds and the province? "Show me the money," Ms. Chow retorts, flashing a lopsided grin from her bout with Ramsay Hunt syndrome, a viral infection that has left part of her face paralyzed.

"That's an old Mel Lastman line," she adds, pointing out that years of studies, including environmental assessments, have to be completed before money flows from other levels of government for the subway. But her quip also underlines her longevity in municipal politics – she was on city council long before the other candidates were even a glimmer in the public eye. First elected as a school trustee in 1985, she won a seat on city council in 1991 and served for 14 years before resigning in 2005; the following year she was third-time lucky for the NDP in the federal riding of Trinity-Spadina.

Making Toronto work more quickly, better and more compassionately is her campaign goal. But how is she going to fix the city's infrastructure without turning herself into the tax-and-spend socialist that her opponents have caricatured?

When Matt Galloway, host of CBC radio's Metro Morning, asked Ms. Chow this week if tax is the new four-letter word, she skidded away from an opportunity to make her case for reinvesting in the city. Instead, she waffled, saying the savings from killing the Scarborough subway would provide the fiscal room to build a downtown relief line, increase bus service at rush hour and expand and improve Toronto Community Housing projects.

Story continues below advertisement

Unlike other major cities – including New York, Madrid, Berlin and Tokyo – Toronto, with its $11-billion operating budget, has a limited range of revenue tools to finance its needs and support its desires to attract global talent and compete internationally, especially since it must, by law, balance its budget.

"We talk a lot about our infrastructure needs, particularly on transit, but we don't talk a lot about how we are going to pay for them," says Enid Slack, director of the Institute on Municipal Finance and Governance at the Munk School of Global Affairs at the University of Toronto. "That is what the new mayor has to do," she says, "but that means using the T-word" – and for Torontonians, that basically means increased property taxes, a highly visible drain on net income. So far, former Scarborough councillor David Soknacki (who agrees with Ms. Chow about the LRT) is the only candidate daring enough to risk an adult conversation about taxes, but he is so far behind that he probably won't be on the final ballot.

Everybody, including Ms. Chow, seems to be running on the presumption that Mr. Ford is finished. Big mistake. A lot can happen before the polls close on Oct. 27, but despite Mr. Ford's disregard for the facts, he won this week's televised debate with his Krazy Glue adherence to his mantra about getting rid of waste and safeguarding taxpayer dollars. And Ms. Chow is the lone contender on the left, staring down a bevy of right-wing opponents.

How much do party affiliations matter in supposedly non-partisan municipal politics when it comes down to that solitary moment in the polling booth? What's right- or left-wing about snow clearance or garbage collection? According to sociologist Mark Granovetter, political designations and even family networks can be weaker than the alliances people form through the causes they espouse and the interests they share at the local level. Rob Ford is a case in point. Returning all those phone calls to his constituents was a huge impetus propelling him into the mayor's office in 2010. The same may well be true of Ms. Chow. Rather than vision, her greatest political strength may turn out to be the decades she spent working on school breakfast programs, daycare, minority rights, community housing – along with her powerful personal story.

Olivia Chow is again in yellow early on a Monday morning at her home on Huron Street. That's the third time in less than a week that she has appeared dressed like a ray of sunshine. "It's my favourite colour," she admits unapologetically, a preference that is borne out by the lemon-curd walls of her kitchen. Painting the bedroom yellow was her only redecorating request when she and Mr. Layton briefly moved into Stornoway, the official residence of the Leader of the Opposition, and as she points out, she chose the lucky yellow tie her late husband wore during the federal leadership debate in the 2011 election.

Now the house is bustling again with volunteers and strategists. This time they're here for Ms. Chow's mayoral bid. And yet there is a feeling that an essential part of her is missing – the charisma that Mr. Layton provided.

Story continues below advertisement

Homesickness helped propel Ms. Chow to abandon backbench rhetoric in Ottawa. "I was very much part of the leader's office," she says about the joined in the heart and the head political style she shared with her husband, admitting she "pulled back quite a bit" after Thomas Mulcair became leader. She didn't contest the leadership because she didn't relish being seen as the Widow Layton. "It didn't feel right to take Jack's place," Ms. Chow says. "I wrote the book to deal with that stuff."

Grief wasn't the only trauma Chow exposed in My Journey. She relayed her own story: the spoiled, middle-class Hong Kong girl who immigrated here in 1970 at age 13 and struggled to learn English; her father's depression and frustration, which found release in beating her mother; her cyclical attraction to abusive boyfriends; and her conversion from religion to social democracy as an assistant to Dan Heap, the MP for Trinity-Spadina. She says her story isn't unusual in immigrant communities, but it adds resonance to her policy work rhetoric and personalizes her political mission as an advocate.

"I know city hall and how it works," she says, gesturing with her hands as though she is massaging a lump of clay. "I feel I can have an impact here."