There were flashes of Biden's hot temper on the campaign trail. Notably, he called one voter a "damn liar", and another a "lying dog-faced pony soldier".
In office, there have been more expressions of bad temper. The president has privately been irritated about not being able to hold in-person meetings with other politicians because of the pandemic, and chafed about the ineffectiveness of Zoom diplomacy.
He has upbraided aides and experts for not knowing the answers to left-field questions, and become exasperated by overly bureaucratic language, occasionally swearing.
President Joe Biden speaks after signing the PPP Extension Act of 2021, in the Oval Office of the White House. Photo / AP
However, there have been no titanic rages on the scale of his predecessor's.
After three months in office, the curtains are starting to be drawn back on the inner workings of Biden's White House.
It has emerged that he demands voluminous amounts of detail on every subject, with some meetings going on for over two hours.
He can then take an extended period of time to make a decision.
President Joe Biden and first lady Jill Biden step off Air Force One at Delaware Air National Guard Base in New Castle. Photo / AP
One person who has been in a face-to-face meeting with him said he asks a lot of questions, but does also "like to talk a lot" himself. "There's a lot of folksy stuff, he can go off on tangents," the person said.
Staff have micro-managed Biden's schedule, putting in 15-minute breaks after meetings, knowing they will inevitably overrun.
At the end of his working day staff give Biden three-ring binders, separated into different topics, with information in 14-point type.
He dutifully reads the files overnight and carries them back himself to the Oval Office in the morning, between 9am and 9.30am.
The president is shadowed by Secret Service agents who use the codename "Celtic" for him. It was chosen by Biden as a tribute to his Irish heritage.
Those who know Biden said he has been determined to set a "blue collar" tone in his White House, one that rewards graft, rather than combative appearances on cable news shows.
"He's always been an incredibly hard worker, and that's what he's doing now," said one person who has known Biden for decades.
"That's how he got there. He always wanted to be a politician and he just worked harder than anyone else. Joe's at his best when the odds are against him."
President Joe Biden and Vice President Kamala Harris during a meeting in the Oval office. Photo / AP
Biden has deliberately chosen low-key officials to be in his inner circle.
They are all people he has known for decades and have long ties of loyalty. Some were his interns when he was a senator.
None of them would be recognised in their local supermarket. But they are the power behind the throne.
The group is led by the two most important gatekeepers - Ron Klain, the White House chief of staff, and Steve Ricchetti, counsellor to the president.
Klain, who started out as a Biden intern, has emerged as the key point of contact for left-wing Democrat members of Congress seeking access to the president, including those pushing the Green New Deal climate change agenda.
He is the regular conduit between Biden and left-wing senators Bernie Sanders and Elizabeth Warren. Klain speaks to both regularly on the phone.
Despite Klain's long history with Biden, the two men are not said to be "buddies". Instead, Klain is someone who has the stature to disagree with the president if necessary.
Senator Bernie Sanders, chair of the Senate Budget Committee. Photo / AP
Ricchetti, a former lobbyist who was chief of staff to Biden when he was vice president, is a "buddy" and plays golf with the president.
Biden effectively has Klain whispering in his left ear, and Ricchetti in his right.
Other key players include the quietly spoken Mike Donilon, chief strategist of Biden's campaign, and now "senior advisor". Others call him Biden's "alter ego".
The president has been heard using the phrase "I agree with Mike" more than once.
Meanwhile, Chris Coons, another former intern of Biden's, who now holds his old Delaware Senate seat, has emerged as a key point man in Congress.
He is used as a go-between for the White House and Republicans and has been dubbed Biden's "consigliere".
Biden's working day begins with the President's Daily Brief [PDB], his classified rundown of the latest US intelligence.
Kamala Harris, whose Secret Service codename is "Pioneer", gets the same briefing.
President Joe Biden takes questions from reporters as he speaks about the Covid-19 vaccination programme, in the State Dining Room of the White House. Photo / AP
The president has a longstanding personal commitment that he always answers his phone if a family member calls, even in a meeting.
That includes his grandchildren, who call him "Pop". He also speaks once a day, usually at night, to his son Hunter.
He has dinner in the early evening with First Lady Jill Biden. She drinks wine, but he does not.
Biden, 78, is determined to run for a second term and is pursuing a fitness regime.
He has a personal trainer, eats salads and protein bars, and drinks orange-flavoured Gatorade.
Biden does bicep curls with weights while watching the morning news on TV, usually CNN, and sometimes while on the phone.
Less healthily, he still has a fondness for peanut butter-flavoured taffy, a boiled candy wrapped in wax paper, which is delivered to the Oval Office from a shop in his home state of Delaware.
