His long, distinguished political career has been full of success, scandals, gaffes and intense heartbreak.
Mr Biden was formally made president by Congress on January 7 after a violent mob of pro-Trump rioters spent hours on running rampant through the Capitol.
He delivered his inaugural address from the Capitol steps that had been overrun by the violent mob two weeks earlier.
Though Trump claimed he has done more in 47 weeks than the Democrat has in 47 years, Biden stayed resolute vowing to “restore the soul of America” and his calm, reassuring demeanour won him the election after three days of uncertainty.
Who is Joe Biden?
Joseph R Biden Jr, was born in working-class mining town Scranton, Pennsylavania in 1942 to a Roman Catholic family.
His father struggled to find work after losing his job as an oil businessman and eventually became a used car salesman to support his wife and Biden’s two brothers and sister.
As a child and teenager, he struggled with a stutter bravely overcoming the affliction through public speaking.
He played American football as a freshman in college and is a sports car enthusiast.
He graduated from the University of Delaware and Syracuse Law School to become a lawyer.
His 2020 bid came four years after he opted against challenging Hillary Clinton in the 2016 Democratic contest so soon after the death of his first son Beau.
Four years older than Mr Trump, Biden will be 78 on inauguration date – the oldest president ever elected for the first time.
Political career highlights so far
Biden was elected to the senate aged just 29. In 1979, he secured the passage of arms limitation agreements between the United States and the Soviet Union, reducing the risk of global nuclear disaster.
He first ran for president in 1988 keeping his campaign centrist and vague to appeal to the majority of American voters.
But his dream fell apart when he was accused of plagiarising some of his speeches including most famously a debate in Iowa where he lifted large sections of then Labour leader Neil Kinnock’s “1,000 generations” speech.
Biden, channelling Kinnock, told the crowds: “Is it because I'm the first Biden in a thousand generations to get a college and a graduate degree that I was smarter than the rest?” He also pointed to his wife in the crowd just as Kinnock did.
Biden later would take the blame for his mistakes during the campaign. “All I had to say was 'Like Kinnock.' If I'd just said those two words, 'Like Kinnock,' and I didn't. It was my fault, nobody else's fault,” he said.
“I've done some dumb things, and I'll do dumb things again.”
In 1994, he sponsored the original Violence Against Women Act leading to a major decline in intimate partner violence, from 2.1 million victims in 1994 to 907,000 in 2010.
The Democrat ran for President again in 2008 but failed to get his campaign off his ground against a youthful, charismatic Barack Obama who promptly made him his vice president for two terms.
As vice president to Obama, he played a pivotal role in lifting the USA out of the Great Recession in 2008 and helped pass the Affordable Care Act, guaranteeing health coverage for Americans with pre-existing conditions and 20 million who were previously uninsured.
A spokeswoman for Obama said he had relied on Biden's "knowledge, insight, and judgment throughout both campaigns and the entire presidency".
He also became a popular meme topic, depicted as a hellraiser compared to Obama’s calm persona, fuelled by his occasional gaffes.
How's he been on the campaign trail
Dismissed as ‘Sleepy Joe’ by Trump, Biden was criticised for spending too much time in the basement during the pandemic. Whilst Trump favoured huge, usually maskless, rallies in the red states, Biden opted for virtual benefits so as not to spread the risk of coronavirus.
Biden is popular in some places Democrats, such as working-class swing states Wisconsin, Michigan and Pennsylvania, his birthplace and the state that tipped him past his necessary 270 votes to win the election.
During the second presidential debate, Biden accidentally referred to far-right militia the Proud Boys as ‘the poor boys' as he attacked Trump's record on tackling racism.
He also confused his wife with his sister on stage at a rally in California in June. “By the way, this is my little sister Valerie!” Biden said while grabbing his wife's right hand. “And I'm Jill's husband,” he went on while reaching for his sister's.
Biden recently faced new questions in regards to greeting strangers at political events, with several women coming forward to say he had made them feel uncomfortable.
He has apologised and said he recognised standards for personal conduct had evolved in the wake of the #MeToo movement.
Biden and Trump went head-to-head twice during the campaigning period. The first US presidential debate descended into an ugly brawl, with Trump repeatedly interrupting Biden and the White House rivals hurling insults at each other as they clashed over everything from the economy and race relations to the coronavirus pandemic.
At one point, Biden became so exasperated he told the president: "Would you shut up, man."
The second debate was a more controlled affair with neither candidate landing a fatal blow to his opponent’s hopes but Biden crucially emerged unscathed. After Trump claimed that no US President had done more for the black community since Abraham Lincoln, Biden countered powerfully: “Abraham Lincoln here is one of the most racist presidents we’ve had in modern history. He’s pours fuel on every single racist fire… This guy has a dog whistle the size of a fog horn.”
Biden is known as a moderate Democrat and Trump’s attempts to paint him as a dangerous left-wing radical have largely failed.
As opposed to Trump, Biden recognises the threat of climate change and has put forward an ambitious, $2 trillion plan to have a carbon-free power sector by 2035 and invest in a green economy.
Biden's plan for health care would attempt to make the Affordable Care Act passed under Obama-Biden easier to navigate with more choices whilst insuring an estimated 97 per cent of Americans.
He opposes Brexit, putting him at odds with Downing Street, and he said a Biden White House would push to protect the Northern Ireland peace deal.
Biden has also put forth several plans to address the coronavirus pandemic, pledging to follow the science and heed the advice of experts.
The month after being first elected senator in a shock victory in 1978, Biden's wife Neilia and their one-year-old daughter Naomi were killed in tragic accident in Hockessin, Delaware.
Biden's sons Beau and Hunter suffered a broken leg and a minor skull fracture, and doctors feared they would never recover.
In his autobiography, Biden wrote that he considered suicide before vowing to survive to raise his remaining sons. He wrote: “Most of all I was numb but there were moments when the pain would cut through like a shard of broken glass.”
Biden thought about quitting his new position to care for the two boys but leading Senator majority leader Mike Mansfield pleaded “just give me six months”.
Reluctantly, Biden agreed and was pictured being sworn in by the hospital bed of his son Beau. He kept the seat for 36 years.
He met his second wife teacher Jill on a blind date arranged by his brother. The couple, both Roman Catholic, were married in 1977 in New York. Their daughter Ashley Blazer is a social worker.
Beau Biden became an army judge advocate in Iraq and later attorney general for Delaware before he tragically died of brain cancer in 2015.
His other son Hunter Biden, a Washington lobbyist, became embroiled in a scandal earlier this month when Rudolph W. Giuliani, President Trump’s attorney, began releasing emails and texts purportedly from Hunter Biden’s laptop.
The messages show that an executive of Burisma Group, a Ukraine energy firm for which Hunter sat on the board of directors, thanked him for setting up a meeting with the vice president in 2015.
An unintentional result of the leaks exposed emotional texts between the father and son showing a human side to Joe Biden.
Messaging his son recovering from drug addiction in rehab, he said: “Good morning my beautiful son. I miss you and love you. Dad.”
When Hunter replies saying his addiction could cost his father the election Joe simply replies: “I’ll run but I need you... Only focus is recovery. Nothing else.”
What did Biden say in his inaugural speech
The new president said: “The will of the people has been heard, and the will of the people has been heeded. We’ve learned again that democracy is precious and democracy is fragile. At this hour, my friends, democracy has prevailed.
“This is America’s day. This is democracy’s day. A day in history and hope, of renewal and resolve.”
The president then turned to challenges ahead, acknowledging the surging coronavirus virus that has claimed more than 400,000 lives in the United States.
Mr Biden did not mention Mr Trump by name in his inaugural address but alluded to the rifts his predecessor had helped create.
Mr Biden said: “I know the forces that divide us are deep and they are real. But I also know they are not new. Our history has been a constant struggle between the American ideal that we all are created equal and the harsh, ugly reality of racism, nativism, fear, demonisation that have long torn us apart.
“This is our historic moment of crisis and challenge, and unity is the path forward and we must meet this moment as the United States of America.”