D.C. Council member Muriel Bowser launched a mayoral bid Saturday, kicking off a year-long Democratic primary campaign that is likely to center on the pace of progress in city government, the ethics of elected officials and the direction of the city’s remarkable growth.

Promising to fight for a “fair chance and a seat at the table” for all District residents, Bowser made her announcement in front of her childhood home in North Michigan Park, a neighborhood of brick duplexes and modest detached homes that have housed working-class, mostly African-American Washingtonians for generations.

“Will you go the distance with me?” Bowser asked a cheering crowd of more than 100 supporters. “It won’t be easy, but we need a change.”

Bowser’s remarks Saturday and in an interview with The Washington Post indicate that the Ward 4 Democrat is designing her campaign to exploit Mayor Vincent C. Gray’s perceived weaknesses — his deliberate bearing and the wide-ranging federal investigation into his 2010 campaign.

Bowser did not mention Gray directly in her announcement but said city residents want a mayor who is “not seduced by the perks of the office or the power that comes with it, but humbled by the opportunity to lead.”

“Corruption has robbed is of our focus, our momentum, our need to think big and act swiftly,” she said. “We’ve settled into the status quo.”

Bowser, a political confidante of former mayor Adrian M. Fenty, becomes the first candidate to officially enter the race, leapfrogging Gray, who could announce a reelection bid before late fall, when candidates begin circulating ballot petitions for the April Democratic primary. Other council members could also enter the contest: Tommy Wells (D-Ward 6) has formed an exploratory campaign, Jack Evans (D-Ward 2) has said he plans to run, and David A. Catania (I-At Large) is pondering a bid.

In an interview before Bowser’s formal announcement, Gray said he “refused to engage” her on campaign issues at this point.

While Gray has not said he will seek reelection, he has laid the groundwork, at least rhetorically, for doing so. He has touted the city’s growth, a spate of economic development projects, and steady progress in some city agencies. His administration has also issued a five-year economic development strategy, a 20-year sustainability plan, a long-term affordable housing framework.

Federal officials have been investigating Gray’s 2010 campaign, including revelations of illegal activity within the campaign as well as the existence of a separate $650,000 “shadow campaign.” Gray has denied any wrongdoing.

Tony Giancola, 67, a retired association executive, said Saturday he is supporting Bowser because he had grown disillusioned by the “taint” of scandal in the Gray campaign.

“We need younger, fresher views of where the city is headed and Muriel is the person to do that,” he said.