"I don't think there's ever been someone so qualified to hold this office. She's got the courage, the compassion, and the heart to get the job done... I have seen her judgement," Obama said in an email and a web video circulated by the Clinton campaign.
"I've seen her toughness. I've seen her commitment to our values up close. And I've seen her determination to give every American a fair shot at opportunity, no matter how tough the fight - that's what's always driven her, and still does," Obama said.
The Clinton campaign also announced their first joint appearance with Obama on the campaign trail next week in Green Bay, Wisconsin.
Obama's endorsement of Clinton came moments after he met Senator Sanders of Vermont at the White House.
Although, Sanders stopped short of endorsing Clinton, but he vowed to work with Clinton to defeat Trump.
"Needless to say, I am going to do everything in my power and I will work as hard as I can to make sure that Trump does not become president of the United States," he said.
Clinton has reached the magical figure of having enough delegates to clinch the nomination of the Democratic Party.
Sanders, however, refused to end his presidential campaign.
"I will, of course, be competing in the D.C. primary which will be held next Tuesday. This is the last primary of the Democratic nominating process," he said.
But he did indicate that he is looking forward to working with Clinton to defeat Trump.
"I look forward to meeting with her in the near future to see how we can work together to defeat Trump and create a government which represents all of us and not just the one percent," Sanders said.
In a personalised email to his millions of supporters, Obama said he knows how hard the job of the president can be.
"That's why I know Hillary will be so good at it," said the US President.
"I don't think there's ever been someone so qualified to hold this office. She's got the courage, the compassion, and the heart to get the job done. (I say that as someone who had to debate her more than 20 times.)," Obama said in the email titled "I'm with Hillary".
"Even after our own hard-fought campaign in 2008, she agreed to serve our country as secretary of state," he said, adding that he can't wait to get out there and campaign for Clinton.
"I've seen her toughness. I've seen her commitment to our values up close. And I've seen her determination to give every American a fair shot at opportunity, no matter how tough the fight - that's what's always driven her, and still does," Obama said.
The Clinton campaign also announced their first joint appearance with Obama on the campaign trail next week in Green Bay, Wisconsin.
Obama's endorsement of Clinton came moments after he met Senator Sanders of Vermont at the White House.
Although, Sanders stopped short of endorsing Clinton, but he vowed to work with Clinton to defeat Trump.
"Needless to say, I am going to do everything in my power and I will work as hard as I can to make sure that Trump does not become president of the United States," he said.
Clinton has reached the magical figure of having enough delegates to clinch the nomination of the Democratic Party.
Sanders, however, refused to end his presidential campaign.
"I will, of course, be competing in the D.C. primary which will be held next Tuesday. This is the last primary of the Democratic nominating process," he said.
But he did indicate that he is looking forward to working with Clinton to defeat Trump.
"I look forward to meeting with her in the near future to see how we can work together to defeat Trump and create a government which represents all of us and not just the one percent," Sanders said.
In a personalised email to his millions of supporters, Obama said he knows how hard the job of the president can be.
"That's why I know Hillary will be so good at it," said the US President.
"I don't think there's ever been someone so qualified to hold this office. She's got the courage, the compassion, and the heart to get the job done. (I say that as someone who had to debate her more than 20 times.)," Obama said in the email titled "I'm with Hillary".
"Even after our own hard-fought campaign in 2008, she agreed to serve our country as secretary of state," he said, adding that he can't wait to get out there and campaign for Clinton.