|Antonio Villaraigosa, center, with his son Antonio Jr. and his wife Corina|
It was an overwhelming victory, with Mr. Villaraigosa receiving 59 percent of the vote to Mr. Hahn's 41 percent.
In Los Angeles, the office of mayor is non-partisan, and both candidates were liberal Democrats with ties to labor unions. Both faced the challenge of attracting voters from across the political spectrum in a multicultural, multiracial city.
They squared off in the runoff after neither gained a majority in the general election in March.
The two-part contest had happened once before, when Mr. Hahn beat Mr. Villaraigosa in a 2001 runoff. Mr. Villaraigosa, a former state assembly member, then won a seat on the Los Angeles city council.
The race was less about issues than character and ability. Each candidate criticized the fundraising tactics of his opponent and Mr. Hahn faced a corruption probe in city hall.
There was also a difference in style. Mr. Hahn is low-key and is generally seen as a good administrator, but a less-than-dynamic politician. He responded to the criticism on election day before the votes were counted.
"You know, maybe I have a charisma deficit disorder, but I think I have done the job the job that people elected me to do," he said.
Mr. Hahn's support had eroded in the black community, one of his bases in the election four years ago. He angered some African-Americans by working to remove the city's black police chief, Bernard Parks. A popular figure, Mr. Parks quickly won a seat on the city council, where he joined Mr. Villaraigosa in attacking the mayor.
Mr. Hahn also angered white voters in the San Fernando Valley, another source of his support, when he opposed a secession measure to create a separate city in that northwestern section of Los Angeles. The measure failed and many pro-secession voters targeted the mayor for removal.
Mr. Villaraigosa, who is 52, is the son of Mexican immigrants. He did not emphasize his Hispanic heritage during the campaign, but often says it is something he takes pride in.
Hispanics make up more than 40 percent of the city's population, but only 20 percent of the electorate. Many are new immigrants and others are under the voting age.
In his acceptance speech, the mayor-elect promised to build bridges between the city's diverse communities.
"Together, we can make a difference, to make this city the city that it can be," he said.
Los Angeles is the second-largest U.S. city, after New York. It is now the largest U.S. city with a Hispanic mayor. The mayor's race here is won by building coalitions, and the candidates made their appeals in English, Spanish, Japanese, and even a little Yiddish.
But for the growing Hispanic population the election marks a coming of age in a city founded by Spanish colonial settlers more than 200 years ago.