He replaces Chicago's longtime mayor, Richard M. Daley, who held office for 22 years. Mayor Emanuel is the city's 55th mayor and Chicago's first Jewish mayor.
"Today, more than any other time in our history, more than any other place in our country, the city of Chicago is ready for change," Mayor Emanuel said Monday at Pritzker Pavilion. He was joined by his wife, Amy Rule, and their three children.
"Over the next four years, we have schools to fix. Over the next four years, we have streets to make safe. Over the next four years, we have a government to transform and businesses and jobs to attract," Mayor Emanuel said. "Chicago is the city of 'yes, we can' -- not 'no, we can't.'"
Mayor Emanuel's first address as mayor -- and much of the inauguration celebration, itself, from the performances of a pint-sized violinist to the Chicago Children's Choir -- focused on the future of Chicago's children.
"There is no doubt the children of Chicago have what it takes. The question is, do we? Will we do our part?" Mayor Emanuel said. "I am confident in Chicago's future because I have seen it in the eyes of our schoolchildren and heard it in their voices."
He said his top priority is fixing the Chicago Public Schools system.
"As some have noted, including Amy, I am not a patient man. When it comes to improving our schools, I will not be a patient mayor," Emanuel said.
Mayor Emanuel's other promises included safer streets, more efficient use of taxpayer money and economic development to create jobs.
Mayor Emanuel said his new police chief will work to prevent violence. "Kids belong in our schools, on our playgrounds and in our parks, not frozen in time on the side of a grim memorial," Emanuel said.
Faced with a major budget deficit, the mayor recalled a bigger crisis- The Chicago Fire-- and how the city rose from the ashes.
"Almost 140 years ago, a great fire devastated Chicago. Some thought we would never recover. An entire city had to be rebuilt from the ground up -- and it was. That is how we earned the title of the Second City," Mayor Emanuel said.
He also spoke about changes in the way government is done. "Given the challenges we face, we need to look for better and smarter ways to meet our responsibilities. So when I ask for new policies, I guarantee, the one answer I will not tolerate is: 'We've never done it that way before.'"
Mayor Emanuel got straight to work Monday afternoon, signing three executive orders: New employees will not be allowed to lobby within two years after leaving the administration, city employees cannot be pressured to make political donations, and lobbyists are not allowed to make political contributions to the mayor.
During Monday's inauguration, Mayor Emanuel also thanked outgoing Mayor Daley for his service.
"Through Mayor Daley's vision, determination and leadership, this place, like our city, was reborn," Mayor Emanuel said. "When Richard M. Daley took office as mayor 22 years ago, he challenged all of us to lower our voices and raise our sights. Chicago is a different city today than the one Mayor Daley inherited, thanks to all he did."
Arriving at Pritzker Pavilion with his wife, Maggie, Mayor Daley said it was a "wonderful day." He and Maggie were cheered as they joined Mayor-elect Emanuel and his family; and U.S. Vice President Joe Biden and his wife, Jill; on stage at Pritzker Pavilion.
The inauguration began with a performance by the Chicago Children's Choir and the U.S. Pledge of Allegiance. Grammy-winner Heather Headley then sang the National Anthem.
At 10:15 a.m., the city's website switched photos from Mayor Daley to Mayor-elect Rahm Emanuel.
Chicago City Clerk Susana Mendoza was sworn in just before 11 a.m. She then swore in the 50 Ward aldermen, 18 of whom are new, to the Chicago City Council.
City Treasurer Stephanie Neely was sworn in around 11:15 a.m.
Emanuel started his day as he does most others- with a 5 a.m. workout, which includes a one-mile swim, and a small breakfast. His family, who still live in Washington, D.C., where Emanuel served as White House chief of staff for President Barack Obama before returning to Chicago, is in town for the festivities.
Public watches Chicago history at Pritzker Pavilion
After a weekend of events across Chicago, Mayor Emanuel's inauguration was held at Pritzker Pavilion. It was open to the public and included several dignitaries.
Several thousand people gathered in the park's Pritzker Pavilion to watch Monday's inauguration ceremony. Hundreds more with tickets stood on the lawn and lined the fence.
While spectators gave outgoing Mayor Daley -- and his wife, Maggie -- a big round of applause, many Chicagoans said it is time for a change in leadership and they hope Mayor Emanuel will get the city back on track.
"I don't know anything but Daley in the mayor's administration. I eat, sleep and thrive Daley and I just wanted to be a part of it," Chevette Valentine said.
Mayor Emanuel's promise of change was welcomed by many.
"I liked what he said he's an impatient man. Because I think that's what we need, someone who can really change Chicago around," Sofia Johnson said.
"He's right we need to do better to educate our children," Gwendolyn Johnson said.
"I'm a huge proponent of his educational reform ideas. I think Chicago Public Schools needs to get its act together a little more," George Symeonides said.
Olivia Haman, 11, got a lesson in history outside of the classroom. Her father brought her to Millennium Park for the inauguration.
"I took Olivia to President Obama's inauguration," Gerald Haman said.
"I think it's important for all kids to see how their own government works, happens in a community, and how it is controlled," Olivia said.
And the Security was tight at Millennium Park. The general public was allowed in from one entrance.
"I feel he's a good, positive influence to the city of Chicago from the way he portrays himself," Majid Kahn said. "I have a lot of faith in him."
"I think he can make it, but he needs a lot of help," Fatima Taneia said.
Mayor Emanuel said all Chicagoans should get involved.
Members of the Chicago's Children's Choir, which performed, spoke with ABC7 before the inauguration began.
"It means a moment in history," Dashawn Wallace, said. Wallace is a member of the West Garfield Park Off the Street Club.
Emanuel's long road back to Chicago
Emanuel first made his desire to be Chicago mayor known more than a year ago when he said if Daley were to retire, he'd run. Daley's announcement he would not seek another term led to Emanuel's departure from the White House and return to Chicago, where he faced residency questions -- much in part due to the fact he rented out his Northwest Side home -- before being added to the ballot.
Emanuel won the election by a landslide, getting 55 percent of the vote. Since his election, Emanuel has kept steady on his search for top hires, including in Chicago Public Schools and Chicago Police Department.