"By almost every measure, America is a better, stronger place" than it was eight years ago when he took office, he told thousands of supporters.
Raucous chants of "four more years" from the crowd were brushed aside by the president. "I can't do that," he said with a smile.
In his closing remarks he said he had one final request for Americans as president: "I am asking you to believe. Not in my ability to bring about change - but in yours."