Biden will be oldest US president to take oath on Inauguration Day 2021

WASHINGTON - When president-elect Joe Biden takes the oath of office Wednesday, he’ll not only face a deadly pandemic that has upended the economy amid searing national division, but he’ll also become the nation’s oldest president in history.

Biden turned 78 in November and will become the oldest president on Inauguration Day, Jan. 20. President Donald Trump previously held the record for the country’s oldest person to become commander-in-chief when he was sworn in at 70 years old in 2017.

Prior to Trump, Ronald Reagan held the title when he was inaugurated at 69 in 1981. During a debate with Walter Mondale during his re-election campaign in 1984, Reagan famously made light of the topic when a moderator asked Reagan whether his age should be an issue in the campaign.

"I want you to know that also I will not make age an issue of this campaign. I am not going to exploit, for political purposes, my opponent's youth and inexperience," he deadpanned, prompting audience laughter.

The youngest person to assume the presidency was Theodore Roosevelt, who succeeded to the office in 1901 after the assassination of William McKinley. He was just 42 years old. 

John F. Kennedy was the youngest person to be elected president. He was sworn in at 43 years old in 1961.

Biden, who faced criticism about his age and mental fitness during the campaign, promised in September to be "totally transparent" about all facets of his health if elected. And his campaign worked to make the case that Biden isn’t your average septuagenarian. 

President-elect Joe Biden speaks during an announcement Jan. 16, 2021 at the Queen theater in Wilmington, Delaware. (Photo by Alex Wong/Getty Images)

His physician, Dr. Kevin O’Connor, in a medical report released by the campaign in late 2019, described Biden as "healthy, vigorous ... fit to successfully execute the duties of the Presidency, to include those as Chief Executive, Head of State and Commander in Chief."

O’Connor reported that Biden was working out five days a week. The president-elect previously told supporters that during the pandemic he has relied on home workouts involving a Peloton bike, treadmill and weights.

RELATED: Biden may have to leave his Peloton in Delaware when he moves into the White House: report

In 1988, Biden suffered two life-threatening brain aneurysms, an experience that he wrote in his memoir shaped him into the "kind of man I want to be." O’Connor also noted in his report that Biden has an irregular heartbeat, but it has not required any medication or other treatment. He also had his gallbladder removed in 2003.

A September article by a group of researchers in the Journal on Active Aging concluded that both Biden and Trump are "super-agers" and are likely to outlive their American contemporaries and maintain their health beyond the end of the next presidential term.

But out of the gate, Biden will need to demonstrate he’s got the vigor to serve, experts say.

"It’s crucial that he and his staff put himself in the position early in his presidency where he can express what he wants with a crispness that’s not always been his strength," Ross Baker, a political scientist at Rutgers University who has advised legislators from both parties, told the Associated Press. "He has got to build up credibility with the American people that he’s physically and mentally up to the job."

Biden’s relatively advanced age also puts a greater premium on the quality of his staff, Baker said. His choice of Sen. Kamala Harris, nearly 20 years younger than him, as vice president effectively acknowledged his age issue. 

"He’s well served in making it known from day one that she’s ready to go," Baker said of Harris. "She’s got to be in the images coming out of the White House. They also need to, in terms of their messaging, highlight her inclusion in whatever the important issue or debate is going on in the White House."

Some of Biden’s White House predecessors left behind breadcrumbs about the dos and don’ts of demonstrating presidential vigor, Edward Frantz, a presidential historian at the University of Indianapolis, told the Associated Press. 

Reagan made sure the public saw him chopping wood and riding horses. 

In 1841, William Harrison, 68, attempted to show off his vigor by delivering a lengthy inaugural address without a coat or hat. Weeks later, Harrison, then the oldest president elected in U.S. history, developed a cold that turned into pneumonia that would kill him just a month into his presidency. It’s disputed, though, whether Harrison’s illness was related to his inaugural address.

Trump, after being diagnosed with the coronavirus in 2020, quickly returned to a busy campaign schedule amid the ongoing pandemic — holding dozens of crowded rallies in battleground states in the final weeks of the campaign.

This story was reported from Cincinnati. The Associated Press reported.