Just before 3:30 p.m., the president arrived at O'Hare Airport on Air Force One. When he got off the plane he was greeted by Chicago Mayor Rahm Emanuel.
From O'Hare, the president boarded Marine One and headed toward Soldier Field, where he was driven the rest of the way to the early polling place at 43rd and South Cottage Grove, the Martin Luther King Community Center, near his Kenwood home.
He arrived at the polling place around 4:15 p.m. When he signed in to vote, he was asked to show ID. Obama replied, "Ignore the fact that there's no gray hair in that picture."
By voting early Thursday in Chicago, the president hopes to encourage others around the country to do the same.
"The president's going coast-to-coast on this 48-hour tour," said presidential advisor David Axelrod. "But he stopped here in Chicago because this is home, and he came to vote, and he wants to set an example for everyone around the country."
For both presidential campaigns, the emphasis is now shifting from wooing undecided voters to ensuring their supporters actually cast ballots.
Thursday, the Obama campaign e-mailed supporters with a personal plea from the President:
"This race is extremely tight," Obama wrote. "It's going to come down to which side can more effectively turn out the vote in these final days, and early vote is a huge part of that. Whether people get out to vote this year, in this election, is even more critical than the last time around."
"I drove to the inauguration by myself in 2008," said Bronzeville resident Andrea Thompson. "The passion I had for him in 2008 is the same as the passion I have for the president that I have now."
Thompson is among the many who lined up to vote at Bronzeville's Martin Luther King Community Center. It's where, Thursday afternoon, Barack Obama will become the first presidential nominee to cast a ballot before Election Day.
Once he's done voting, President Obama will be making one more unannounced stop, Axelrod told ABC7.
The 48-hour journey has already included a midnight stop in Nevada. On Wednesday, President Obama also stopped in Iowa and California, where he appeared on the Tonight Show with Jay Leno to talk about his hectic, coast-to-coast trip that spans 6,500 miles.
"I am going to stop in Chicago to vote because Illinois has early voting... It means you don't have to take off work or figure out how -- picking up the kids and all that stuff," President Obama said on the show.
Although Election Day is 12 days away, Illinois is one of the states offering early voting. Polling locations have seen record numbers of residents lining up each day since early voting began on October 22, according to Cook County election officials.
Some early voters in line at Martin Luther King Community Center were determined to cast their ballots at the same location where President Obama will vote Thursday.
"I'm very, very excited. I just wish I had the chance to meet President Obama face-to-face, you know shake his hand or something to let him know I'm out here supporting him," said Tasha Lee, early voter.
"I came here the other day after 4 p.m., and it was still crowded. So I got a little taste of it then. I did not know this was happening this morning," said Harrison Smith, early voter.
President Obama began the day in Florida. Then, he will travel to Virginia. He will spend less than three hours in Chicago before heading to the battleground state of Ohio.
Republican rival Mitt Romney will also campaign in Ohio Thursday. Analysts believe the swing state will play a pivotal role in the results of the election.