Mr Biden made the comments during a press conference on Thursday.
The president said he was familiar with the Chinese leader from his days as vice president under Barack Obama.
“He doesn’t have a democratic – with a small ‘d’ – bone in his body, but he’s a smart, smart guy,” Mr Biden said.
Mr Biden also compared the Chinese leader to Russian President Vladimir Putin.
“He’s one of the guys like [Russian President Vladimir] Putin, who thinks that autocracy is the wave of the future [and that] democracy can’t function in an ever complex world,” he said.
The president pledged to prevent China from becoming the “wealthiest” and “leading” country in the world by leaning on allies and boosting the US’s investment in technology.
“I see stiff competition with China,” Mr Biden said. “China has an overall goal, and I don’t criticise them for the goal, but they have an overall goal to become the leading country in the world, the wealthiest country in the world and the most powerful country in the world. That’s not going to happen on my watch, because United States is going to continue to grow and expand.”
The president said the competition between the countries would be one of democracy versus autocracy.
“We’re not looking for confrontation, although we know there will be steep, steep competition,” he said. “This is a battle between the utility of democracies in the 21st century, and autocracies.”
Mr Biden and Mr Xi spoke for the first time since the former’s election during a phone call in February.
According to a White House synopsis of the call, the men discussed Mr Biden’s concerns about Beijing’s stifling of democratic demonstrations as well as human rights abuses and economic practices.
The call “underscored his fundamental concerns about Beijing’s coercive and unfair economic practices, crackdown in Hong Kong, human rights abuses in Xinjiang, and increasingly assertive actions in the region, including toward Taiwan,” according to the White House.
Mr Biden has referred to China as the US’s “most serious competitor”.
The Chinese state news agency, Xinhua, said Mr Xi expressed a desire to improve US-China relations after four contentious years of Donald Trump’s sabre-rattling.
“You have said that America can be defined in one word: Possibilities. We hope the possibilities will now point toward an improvement of China-US relations,” Mr Xi reportedly said.
Mr Xi reportedly also said that the “US side should respect China’s core interests and act prudently”.