Antonio Villaraigosa (search) formally took his oath as the city's 41st mayor on Friday, becoming the first Hispanic to hold the office since the 19th century.

"Angelenos, we need to start thinking big again," Villaraigosa said in an address that contrasted the city's standing as "the undisputed commercial and cultural capital" with "a darker truth" of declining quality of life and problems with education, safety and transportation.

The oath was administered in a ceremony on the steps of City Hall as the man Villaraigosa ousted after one term, fellow Democrat James K. Hahn, and his predecessor, Richard Riordan, looked on.

The audience of political figures included Gov. Arnold Schwarzenegger (search), former Vice President Al Gore (search), former California Govs. Gray Davis, Pete Wilson and Jerry Brown, now mayor of Oakland, and former U.S. Secretary of State Warren Christopher (search).

Villaraigosa's first show of leadership came quickly, when audience members jeered his acknowledgment of Schwarzenegger.

"Excuse me," the new mayor interjected firmly. "There will be civility today."

Villaraigosa reiterated his campaign themes of challenging a status quo that has tolerated dead-end schools, persistent gang crime and snarled traffic, and of uniting a sprawling city divided by geography, wealth and color.

"Believe me, early in our campaign, there were those who said it wasn't time yet for a Latino mayor," he said. "The faith you have placed in me makes me so proud to be an Angeleno today, and I promise you I will be a mayor for all the people."

The charismatic Villaraigosa, 52, is promising to reinvigorate the office after the uneven term of Hahn, who was best known for not being known at all. Villaraigosa ousted him in a May runoff, carrying most of the city's neighborhoods and showing that a big-city Hispanic candidate could attract votes from across the racial spectrum.

At a recent hearing on schools, over which the mayor has no authority, Villaraigosa promised to "use this bully pulpit to hold people accountable." For inspiration he looks to the city's first black mayor, Tom Bradley, who built support for downtown development, subway construction and the 1984 Olympics.

Bradley "was a uniter of people. He wasn't afraid to tackle big problems and take risks," Villaraigosa said. An aging Bradley counseled Villaraigosa years ago, "Don't quit what you are doing."

Despite his sudden celebrity, Villaraigosa assumes an office known for its lack of clout. The City Council here can block decisions made by mayoral commissions that run agencies, including the police and fire departments.

Education, a top issue for voters, is run by the Los Angeles Unified School District. County supervisors hold a strong hand in health care and law enforcement. The Metropolitan Transportation Authority runs the buses and subways.

In a low-turnout election, Villaraigosa, a city councilman and former state Assembly speaker, won 59 percent of the vote after broadening his Hispanic base to include significant numbers of blacks, along with white liberals and moderates.