Clinton also warned that a Trump presidency would hurt the economy, noting that economists say the presumptive Republican presidential nominee would "would throw us back into recession."
"Just like he shouldn’t have his finger on the button, he shouldn’t have his hands on the economy," Clinton said, comparing Trump's danger to national security to his potential impact on the economy.
Clinton bashed Trump's businesses practices, noting that he has filed for bankruptcy several times.
"He's written a lot of books about business. They all seem to end at Chapter 11," she said.
"We cannot put a person like this, with all his empty promises, in a position of power over our lives," she added. "We can’t let him bankrupt America like we are one of his failed casinos. We can't let him roll the dice with our children's futures."
Clinton said that Trump is full of empty promises, noting that he's being sued for fraud by former students at his notorious Trump University.
"Now he's trying to say he's changed. Somebody’s told him he needs to say that— that he's not in it for himself anymore," she said. "But he's doing the exact same thing he's been doing for years. This is his one move. He makes over the top promises that if people stick with him, trust him, listen to him, put their faith in him, he'll deliver for them, he'll make them wildly successful."
"And then everything falls apart and people get hurt," she continued. "Those promises you're hearing from him at his campaign rallies, they are the same promises he made to his customers at Trump University. And now they're suing him for fraud. The same people he's trying to get to vote for him are people he's been exploiting for years."
Throughout Clinton's speech, Trump responded to Clinton with several tweets, and his campaign sent out several press releases on Clinton's record and Trump's economic plan.
How can Hillary run the economy when she can't even send emails without putting entire nation at risk?
— Donald J. Trump (@realDonaldTrump) June 21, 2016
Clinton also used the speech to criticize Trump's policy proposals, arguing that he would roll back Wall Street regulation.
"Trump would take us back to where we were before the crisis. He’d rig the economy for Wall Street again," she said. "Well, that will not happen on my watch, I can guarantee you.”
She said that Trump calls himself the "King of Debt," noting that his tax plan would increase the national debt. She referenced a May interview in which Trump suggested he would try to "make a deal" and renegotiate the country's debt.
"It's like he said, ‘You know, you make a deal before you go into a poker game.’ Well, actually, it's not like that at all. The full faith and credit of the United States is not something we just gamble away. That could cause an economic catastrophe," she said. "And it would break 225 years of ironclad trust that the American economy has with Americans and with the rest of the world. Alexander Hamilton would be rolling in his grave."