Davis decided to be a candidate after receiving an endorsement from the Chicago Coalition for Mayor, a group of elected officials, as well as religious, labor and community organization leaders.
The congressman said his focus includes improving schools, employment and city finances.
"Where do we get the money that we need, trying to balance the budget, operating at a deficit? This is the time that, I think, requires visionary leadership," said Davis. "I am running for mayor of the city of Chicago."
The Chicago Coalition for Mayor has been meeting since Mayor Daley announced in September that he wouldn't seek re-election. Leaders say the goal of the coalition was to unify the city's black community behind a "consensus candidate."
But the candidates who weren't selected have signaled they'll continue their plans to run for mayor, even without coalition support.
Former U.S. Carol Moseley Braun, for example, cut a ribbon Saturday to open her first campaign office in her bid to become mayor. The office is located in Chicago's Bronzeville area.
Moseley Braun says she will formally announce her candidacy after she files the required number of signatures on nominating petitions. So far, she's hired two veteran political operatives with connections to Mayor Richard Daley and a one-time aide to former Gov. Rod Blagojevich.
Victor Reyes is a Daley supporter and head of the Hispanic Democratic Organization. Mike Noonan, who helped elect Lisa Madigan attorney general, will serve as Braun's campaign manager.
Louanner Peters was deputy governor under Blagojevich for about two years.
Moseley Braun, a former state lawmaker and U.S. ambassador, cited her local, national and international experience in her "Carol for Chicago" campaign.
"We're gonna provide jobs in the neighborhood, and quality schools for our children, and involve and engage the talent and the minds of all of these magnificent people in developing the direction our city's going to take," Moseley Braun said.
Another candidate, former city colleges board chairman Gery Chico joined his backers on the South Side Saturday in seeking signatures for his petitions.
(The Associated Press contributed to this report.)