"We now have the chance to elect a 45th president who will build on our progress, who will finish the job," Obama told attendees at a rally in Philadelphia.
He said that Clinton is "as well prepared as anyone who has ever run—more than me, more than Bill," and praised her experience before pivoting to discuss the election itself.
"At times, it's felt more like a reality show or even a parody," Obama said. "The choice you face when you step into that voting booth could not be more clear and could not be more serious."
He said that voters have an "outstanding" candidate to vote for in Clinton.
Obama went on to slam "crazy attacks and double standards" leveled against Clinton.
"I've had to bite my tongue," he said.
He criticized Republican leaders for praising Clinton's work as secretary of state yet turning to attack her when it became "politically expedient," exhorting voters to pay attention to down-ballot races.
"You cannot just put Hillary with Republicans in Congress who promise more dysfunction in Washington. It would be hard to do, but they are promising it," Obama said.
He ended his address by recounting a question from a journalist who asked Obama if he still believed in change.
"Yes," Obama said. "I still believe in hope and I'm still as optimistic as ever about the future and that's because of you, the American people."
"I always had the better odds, because I always got to bet on you," he added. "I am betting that, tomorrow, you will reject fear and choose hope."