He said her Republican opponent Donald Trump was a threat to hard-earned civil rights.
President Obama was speaking at a rally in North Carolina.
Mr Trump said Mr Obama should stop campaigning for Mrs Clinton and focus on running the country.
"The bottom line is, no-one wants four more years of Obama," he told supporters in Pensacola, Florida.
He said Mrs Clinton had become "unhinged" in recent days.
Americans will vote for the candidate they want to see in the White House next Tuesday, with recent polls showing the race tightening between Mrs Clinton and Mr Trump.
"The fate of the republic rests on your shoulders," President Obama told supporters in the key battleground state of North Carolina.
"The fate of the world is teetering and you, North Carolina, are going to have to make sure that we push it in the right direction.
"I am not on the ballot, but I tell you what - fairness is on the ballot; decency is on the ballot; justice is on the ballot; progress is on the ballot; our democracy is on the ballot."