"How can there be pleasure from saying, 'You're fired'?" Biden asked. "He's trying to tell us he cares about the middle class? Give me a break. That's a bunch of malarkey."
The man who aims to succeed him, Sen. Tim Kaine of Virginia, ridiculed the Republican nominee for repeatedly saying "believe me" after making outlandish promises. "You cannot believe one word that comes out of Donald Trump's mouth — not one word," Kaine said.
For independent-minded, college-educated voters, New York's former Republican mayor Michael Bloomberg mocked Trump's business record and even questioned his mental stability. Conceding disagreements on issues with Clinton and the Democratic platform, he emphatically endorsed her nevertheless.
"As an Independent, I am asking you to join with me," Bloomberg said. "Not out of party loyalty, but out of love of country. And together, let's elect a sane, competent person."
The night's final speaker was President Barack Obama, appearing 12 years after he burst onto the national stage with his keynote address at the 2004 Democratic convention. He made fun of Trump as "not a plans guy" or "a facts guy," casting him as a "homegrown demagogue" playing on the fears of an anxious nation.
The president, buoyed by approval ratings that now top 50 percent, tried to reassure Americans feeling left out by economic shifts and cultural change. "We're not done perfecting our union," he said.
But he described Hillary Clinton as the right person to keep trying, someone equipped by a lifetime of public service to make progress on domestic issues and win the fight against the Islamic State in Iraq and al-Sham.
"There has never been a man or a woman more qualified than Hillary Clinton to serve as president of the United States of America," Obama said, saying he is ready to "pass the baton" to her.
The one-time rivals from the 2008 campaign then embraced on stage. In the convention's final act Thursday night, Clinton will take the stage and address the nation on her own.