Mrs Clinton appeared on stage in Philadelphia last night
US President Barack Obama has endorsed Hillary Clinton to succeed him in the White House by saying she is the most qualified nominee ever - including him and her husband Bill.
Mr Obama told the Democratic Convention in Philadelphia: "I can say with confidence, there has never been a man or woman more qualified, not me or Bill, to be the President of the United States of America."
Referring to the choice facing the American people with Donald Trump as the Republican candidate, Mr Obama said: "This is not a typical election. It's a fundamental choice as to who we are as people."
The President compared Mr Trump's lack of political experience with Mrs Clinton's years of public service, including many years being "in the room" as top-level decisions were made.
When the crowd booed as he talked about Mr Trump, he responded: "Don't boo, vote."
Mr Obama made several appeals for voters not to let apathy put Mr Trump in the White House in November, saying: "Democracy isn't about yes he will, it's about yes we can."
In a rousing finale to his 40-minute speech, the president urged: "Carry her the same way you carried me. I'm asking you to reject cynicism and...to elect Hillary Clinton as the next President of the United States and show the world we believe in the promise of this great nation."
Immediately after he finished speaking, a surprised audience erupted as Hillary Clinton came on stage for her first live appearance at the convention.
Mr Obama took to the stage after Tim Kaine accepted his party's nomination for Vice President and confessed he "never expected to be here".
Earlier, current Vice President Joe Biden became visibly angry as he talked about Republican nominee Donald Trump, saying it was a "bunch of malarkey" that the billionaire represented working people.
"He has no clue, period," said Mr Biden, prompting chants of "Not a clue, not a clue" from a conference hall that was loving every minute of a speech from one of their favourite sons.
Mr Biden went on: "No nominee in the history of the country has known less or has been less prepared to deal with our national security."
The convention also heard from former New York Mayor Michael Bloomberg, who also did not hold back in laying into his fellow business tycoon.
"Throughout his career, Trump has left behind a well-documented record of bankruptcies, thousands of lawsuits, angry shareholders and contractors who feel cheated, and disillusioned customers who feel ripped off. Trump says he wants to run the nation like he's run his business. God help us."
Mr Trump had overshadowed proceedings on day three of the convention prior to Mr Obama's speech by encouraging Russia to spy on government e-mails.
It follows an accusation the country may have been involved in leaks that have embarrassed the Democrats over the last few days.