The 42nd U.S. president and former Arkansas governor criticized Trump's response to the COVID-19 pandemic, underscoring that the United States has the most cases and most deaths of any nation in the world and is experiencing more significant economic hardship.
"Donald Trump says we're leading the world. Well, we are the only major industrial economy to have its unemployment rate triple," Clinton said, speaking remotely as most convention events have moved online due to the pandemic. "At a time like this, the Oval Office should be a command center. Instead, it's a storm center.
"There's only chaos. Just one thing never changes -- his determination to deny responsibility and shift the blame. The buck never stops there."
"Our party is united in offering you a very different choice: a go-to-work president. A down-to-earth, get-the-job-done guy," he said, contrasting Biden to Trump. "A man with a mission: to take responsibility, not shift the blame; concentrate, not distract; unite, not divide."
Clinton's remarks came shortly before a roll call of all states and territories that formally sealed Biden as the Democratic Party's presidential nominee. In the end, Biden secured 2,687 delegates and former candidate Sen. Bernie Sanders just under 1,100.
Freshman Rep. Alexandria Ocasio-Cortez of New York symbolically nominated Sanders for president on Tuesday night, which is required by Democratic Party rules for any candidate who secured at least 300 pledged delegates during the primary process.
During her speech of under 2 minutes, Ocasio-Cortez gave thanks for a "mass people's movement working to establish 21st century social economic and human rights, including guaranteed healthcare, higher education, living wages and labor rights for all people in the United States."
"In a time when millions of people in the United States are looking for deep systemic solutions to our crises of mass evictions, unemployment and lack of healthcare and espiritu del pueblo and out of a love for all people, I hereby second the nomination of Sen. Bernard Sanders of Vermont for president of the United States of America," she said.
The procedural requirement caused some confusion among viewers who were unaware that the party asked Ocasio-Cortez to second Sanders' nomination as a matter of rule.
"If you were confused, no worries! Convention rules require roll call & nominations for every candidate that passes the delegate threshold," she tweeted. "I was asked to 2nd the [nomination] for Sen. Sanders for roll call. I extend my deepest congratulations to Joe Biden -- let's go win in November."
Following the roll call, Biden was formally invited to the convention to deliver his acceptance speech, which he will do from his home state of Delaware on Thursday.
"Thank you very, very much from the bottom of my heart, thank you all. It means the world to me and my family and I'll see you on Thursday," Biden said alongside his wife, Jill, and his grandchildren.
Colin Powell, former secretary of state under President George W. Bush, spoke in support of Biden, saying the longtime senator and former vice president will trust American diplomats and the intelligence community, rather than flattering dictators.
"I support Joe Biden because on day one he will restore America's leadership and our moral authority. He'll be a president who knows America is strongest when, as he has said, 'We lead both by the power of our example and the example of our power,'" Powell said. "He will restore America's leadership in the world and restore the alliances we need to address the dangers that threaten our nation, from climate change to nuclear proliferation."
Jill Biden, a longtime educator, said in her address that she's been heartbroken by the loss of life during the health crisis and expressed sadness that students have not yet been able to safely return to classrooms. She pledged that her husband will lead the drive for change.
"We need leadership worthy of our nation, worthy of you. Honest leadership to bring us back together -- to recover from this pandemic and prepare for whatever else is next," she said. "Leadership to reimagine what our nation will be.
"That's Joe. He and Kamala will work as hard as you do, every day to make this nation better. And if I have the honor of serving as your first lady, I will too."
Sen. Kamala Harris of California is Biden's vice presidential running mate.
The second day of the convention included meetings of the LGBTQ, rural and Native American caucuses and the veterans and military families, climate crisis and Jewish councils.
Wednesday night's main speakers will include former President Barack Obama, former Secretary of State Hillary Clinton and vice presidential nominee and California Sen. Kamala Harris.
Biden will face Trump in the Nov. 3 election.