"I believe it's always a worthwhile endeavor to promote and boost the United States of America and invite the world to come see what we're all about," he said.
The people working for Chicago to win the games "put in their heart and soul into this bid," said Mr. Obama.
"I have no doubt that it was the strongest bid possible, and I'm proud that I was able to come in and help make that case in person," he said.
Conservative critics have suggested that the president should not have made the trip. House Minority Leader John Boehner knocked the president for "going to go off to Copenhagen when we've got serious issues here at home that need to be debated," while Republican National Committee chair said the move was "not necessarily helpful and doesn't, in my view instill the confidence in the American people that the focus is there on jobs, wealth creation and moving us beyond a recession to prosperity."
Some conservatives greeted the news that Chicago had lost the games as a rebuke of the president. "THE EGO HAS LANDED: WORLD REJECTS OBAMA" trumpeted the conservative Drudge Report Web site, while conservative blogger Erick Erickson of Redstate, as the Huffington Post noted, wrote this: "Hahahahaha. I thought the world would love us more now that Bush was gone. I thought if we whored ourselves out to our enemies, great things would happen. Apparently not. So Obama's pimped us to every two bit thug and dictator in the world, made promises to half the Olympic committee, and they did not even kiss him."
In his remarks, the president congratulated Rio de Janeiro and said he told the Brazil's president "that our athletes will see him on the field of competition in 2016."
"One of the things that I think is most valuable about sports is that you can play a great game and still not win," he said. "And so, although I wish that we had come back with better news from Copenhagen, I could not be prouder of my home town of Chicago, the volunteers who were involved, Mayor Daley, the delegation and the American people for the extraordinary bid that we put forward."
Earlier on Air Force One, White House press secretary Robert Gibbs said Mr. Obama had seen the news on television and was disappointed.
"But I think he feels obviously proud of his wife for the presentation that she made, and doesn't shy away from promoting America in this event or in any other venue as a way to showcase this country," he said.
Asked if it was the right decision to make the trip, Gibbs said, "absolutely."