With 68% of precincts reporting, Emanuel had 56% of the unofficial vote to about 44% for Garcia.
Tuesday's election capped a hard-fought, nationally watched six-week campaign that featured Emanuel in a fight for his political life against Garcia, who has presented himself as the more compassionate option. The contest was the nation's latest proxy battle between establishment Democrats, represented by the mayor, and progressives, who backed Garcia.
Emanuel held a massive campaign fundraising advantage, and he used it to try to cast the race as a referendum on whether Garcia had enough leadership experience to run the city and deflect attention from the controversial decisions and abrasive style that marked the mayor's first term.
All told, Emanuel raised nearly $23 million, compared with a little more than $6 million for Garcia. That allowed Emanuel to get on the air quickly after the first round of balloting Feb. 24 to define Garcia for voters before the challenger had a chance to define himself and capitalize on the momentum generated by forcing the mayor into a runoff.
The mayor has run a nonstop stream of TV ads since November, including more than 20 different spots that have aired more than 7,000 times.
Chicago's mayoral race has gotten attention, both locally and nationally, given Emanuel's stature as a former top aide to Presidents
Garcia is representing the progressive wing of the Democratic Party against the establishment Emanuel wing, adding a new dynamic to the untested nature of a one-on-one mayoral runoff election.
"This is a big election, with clear choices," Emanuel told reporters at a Lakeview campaign office, with a backdrop of volunteers calling potential voters. "There's a lot at stake for the city of Chicago."
Defending his Democratic credentials, Emanuel pointed to backing from some elements of organized labor, his support for raising the minimum wage and having real estate developers set aside money for affordable housing.
"That is what people are voting for -- they're voting for the basic things that they want for their families, their neighborhoods and their communities," said Emanuel, who added, "Yes, my name's on the ballot. That's also true. Chuy's name is on the ballot. But what's on the ballot is Chicago's future. That's what's on the ballot."
Garcia, his voice deteriorating after a weekend illness, stopped at one of his campaign offices near Pullman to encourage supporters.
"We weren't supposed to be here. We were counted out by the pundits, by the polls," said Garcia, a Cook County commissioner and former alderman and state senator.