David Plouffe, manager of President Barack Obama’s 2008 presidential campaign, answers questions from the audience at the First Parish Church yesterday after speaking about his new book “The Audacity to Win.”

A commitment to defying political convention and reaching voters in new ways were key to President Barack Obama’s victory last year, the president’s campaign manager David Plouffe told an audience at First Parish Church last night.

Plouffe, who has also helped to elect mayors, governors, and representatives across the country, was promoting his book, “The Audacity to Win,” as part of a speaker series presented by the Harvard Book Store.

The book provides an inside story of the campaign and lessons from the election from Plouffe’s perspective.

The campaign staff originally thought third place was the best it could hope for in the Democratic primaries, Plouffe said.

Nevertheless, he said, Obama’s team remained focused on its message and electoral strategy.

“Forty-seven percent of America disagreed with us but we had to win,” said Plouffe. “Every candidate has the responsibility to run a campaign to win.”

Plouffe also stressed the campaign’s new approach to reaching out to voters by deviating from conventional means and remaining receptive to new strategies, such as analyzing demographic data to best reach swing voters.

“We didn’t have a dusty playbook on the shelf about how we or how anyone should run a campaign,” Plouffe said. “We probably won’t be using the same one four years from now either.”

Throughout the book and last night’s presentation, Plouffe addressed what he said were four fundamental threads to Obama’s election: belief in the campaign’s ability to defy political convention, refusal to judge success by the news and politics of the moments, the power of the grassroots campaign, and Obama’s performance as a whole.

“We had a belief in a long-term strategy of not being buffeted by the winds of the moment,” Plouffe said.

Daniel A. Habtemariam, a Newton resident who worked on the campaign, was not fully satisfied with Plouffe’s presentation.

“He spoke really well but he’s not as nuanced and professorial as President Obama,” Habtemariam said.

“Many of his answers were hamhocked and media-based instead of the data-based answers I was expecting,” he said.

Tessa L. Simonds of North Hampton was more positive.

“It’s a campaign that we are all still trying to evaluate and be inspired by. It was engaging to hear David Plouffe speak on it.”