In November, 2004, campaign junkies were invited to gather at a bar near Vancouver City Hall to watch the U.S. election results and to meet a rising young political star in the Lower Mainland.

That night, things did not go so well for John Kerry in the United States, but it was the beginning of a series of triumphs for Gregor Robertson. Shortly afterwards, the founder of the Happy Planet organic-juice company went on to defeat a well-known union leader for the NDP nomination in Vancouver-Fairview and then to win the riding.

The man who had invited everyone to come out that evening was Mike Magee, a relative unknown in politics. Four years later, Mr. Robertson is now the mayor of Vancouver and Mr. Magee has risen with him.

He has been a close adviser of Mr. Robertson’s over the years, as well as a family friend. He is one of the key architects of the new Vision Vancouver party that now rules the city’s council, school board and park board. And he is the mayor’s chief of staff, determined to set a new direction at city hall and foster a new culture.

Every successful mayor has a strong chief of staff in the background, someone who knows what the mayor is thinking before the mayor does. But, even in that context, many people say Mr. Magee and Mr. Robertson are so intertwined that they don’t know where one ends and the other begins.

That leads some to believe that Mr. Magee is running the show – but close observers say that’s not the case.

“They’re an interesting pair. They’re not aggressive, domineering types, so when they debate, it’s kind of slow-motion polite sumo wrestling. There’s a slow engagement,” says Andrea Reimer, a former Green Party member and now a city councillor. “But I’ve never seen Gregor lose an argument to him.”

Ms. Reimer herself was prodded to join Vision Vancouver, with its rosy election prospects, by Mr. Magee – part of his larger concept of creating a new form of civic politics.

Mr. Magee, who has worked in the peace, anti-apartheid, anti-gun, environmental and social-change movements in Ontario and British Columbia for the last 20 years, looks to San Francisco Mayor Gavin Newsom and Toronto Mayor David Miller as potential models for this Third Way version of local government.

“We’re trying to achieve a place where the old labels fall away,” says the 44-year-old, who calls Mr. Newsom an old family friend. “We’re really trying to get away from that. And we’re quite clearly positioned as a progressive centrist party with strong social values and strong environmental values.”

Certainly, he helped to engineer a coalition among Vision, the traditional left-wing Coalition of Progressive Electors, and the Green Party that hasn’t been seen before in the city.

And, before that, people in Vision Vancouver say he is one of the main reasons that the party – which started in the spring of 2005 as a breakaway group within COPE led by then-mayor Larry Campbell – exists today.

“Mike has been the leader from day one. He drove it forward,” said Bob Penner, the owner of Strategic Communications, a polling company that has been integral to Mr. Robertson’s political victories. “It’s not easy to construct a party. The leadership skills needed are more demanding.”

Councillor Geoff Meggs, Mr. Campbell’s former chief of staff, said Mr. Magee became a “bit of a rainmaker” for the party, able to pull in money through his connections to the city’s social-enterprise movement, whose most prominent member is the American-born philanthropist Joel Solomon.

Mr. Magee grew up in the working-class Toronto suburb of Weston and was a serious minor-hockey player in his teens and early 20s. But after starting university at York, he became active in grassroots politics. By 1991, he was the head of the Toronto Disarmament Network.

He became friends with Mr. Penner in those years and with Bill Tieleman, a onetime roommate, who is now a B.C. left-wing pundit and communications strategist.

Mr. Magee moved to B.C. in 1994 when his then-wife started work with Greenpeace, and he was soon involved in the Coalition for Gun Control and the Sierra Legal Defence Fund.

In 2000, he started his own consulting company, Convergence Communications, which now does about a fifth of its business with Mr. Solomon’s Renewal Partners and the various companies it funds, and considerable work with Tides Canada, a foundation that advertises itself as promoting economic-justice programs and environmental stewardship. He met Mr. Robertson, whose Happy Planet company got investment money from Mr. Solomon, through that connection.

He’s an enigma to many, a man who looks like a successful middle manager, with his suits and trim goatee, but who has spent decades in social-change movements – someone who talks tough in negotiations but also talks about empowering citizens.

He describes Mr. Solomon as a “dear friend and colleague.” But he shudders when the two of them are jokingly referred to as part of the Hollyhock mafia around Mr. Robertson, in reference to the new-age Cortes Island retreat that offers everything from karma yoga to leadership courses for those wanting to create social change.

“I hate the term New Age,” Mr. Magee says. “It makes my Weston roots come out when I hear that.”