Biden, 77, was introduced by a video that went through the former vice president's life, and career, and highlighted his role as a father, husband and political leader.
Joe Biden pledged that he will be an "ally of the light" as he officially accepted the presidential nomination of the Democratic Party, urging the American voters to unite to overcome a "season of darkness" that President Donald Trump has cloaked the US for "much too long".
On the final day of the four-day virtual Democratic National Convention on Thursday night, Biden, 77, was introduced by a video that went through the former vice president's life, and career, and highlighted his role as a father, husband and political leader.
"It is with great honour and humility that I accept this nomination for President of the United States of America. But while I will be a Democratic candidate, I will be an American president. I will work as hard for those who didn't support me as I will for those who did," he said.
"Here and now I give you my word. If you entrust me with the presidency, I will draw on the best of us, not the worst. I will be an ally of the light, not the darkness," said Biden, who has already scripted history by selecting Indian-origin Senator Kamala Harris as the first Black person as the vice presidential nominee of a major party.
Biden's children, Ashley Biden and Hunter Biden, spoke before their father accepted the nomination.
"America's history tells us that it has been in our darkest moments that we've made our greatest progress. That we've found the light. And in this dark moment, I believe we are poised to make great progress again. That we can find the light once more," Biden said.
"I have always believed they can define America in one word: Possibilities. That in America, everyone, and I mean everyone, should be given the opportunity to go as far as their dreams and God-given ability will take them. We can never lose that. In times as challenging as these, I believe there is only one way forward.
"As a united America. United in our pursuit of a more perfect Union. United in our dreams of a better future for us and for our children. United in our determination to make the coming years bright," he said.
Launching a scathing attack on President Trump, Biden said that the current president has cloaked America in darkness "for much too long".
"Too much anger. Too much fear. Too much division. Here and now, I give you my word: If you entrust me with the presidency, I will draw on the best of us not the worst. I will be an ally of the light not of the darkness," he said.
"It's time for us, for We the People, to come together. For make no mistake. United we can, and will, overcome this season of darkness in America. We will choose hope over fear, facts over fiction, fairness over privilege," Biden said.
Noting that the job of a president is to represent all Americans and not just the base or the party, Biden said: "This is not a partisan moment".
"This must be an American moment. It's a moment that calls for hope and light and love. Hope for our futures, light to see our way forward, and love for one another," he said.
"America isn't just a collection of clashing interests of Red States or Blue States. We're so much bigger than that. We're so much better than that. Nearly a century ago, Franklin Roosevelt pledged a New Deal in a time of massive unemployment, uncertainty, and fear,” he added.
Biden said that his campaign was not just about winning votes, but winning "the heart, and the soul of America".
"Winning it for the generous among us, not the selfish. Winning it for the workers who keep this country going, not just the privileged few at the top. Winning it for those communities who have known the injustice of the 'knee on the neck'. For all the young people who have known only an America of rising inequity and shrinking opportunity," he said.
"They deserve to experience America's promise in full. No generation ever knows what history will ask of it. All we can ever know is whether we'll be ready when that moment arrives. And now history has delivered us to one of the most difficult moments America has ever faced. Four historic crises. All at the same time. A perfect storm,” he said.
"The worst pandemic in over 100 years. The worst economic crisis since the Great Depression. The most compelling call for racial justice since the 60's. And the undeniable realities and accelerating threats of climate change. So, the question for us is simple: Are we ready? I believe we are," he said.
Noting that all elections are important, Biden said that this one, however, is more consequential.
"America is at an inflection point. A time of real peril, but of extraordinary possibilities. We can choose the path of becoming angrier, less hopeful, and more divided. A path of shadow and suspicion," he said.
"Or we can choose a different path, and together, take this chance to heal, to be reborn, to unite. A path of hope and light. This is a life-changing election that will determine America's future for a very long time. Character is on the ballot. Compassion is on the ballot. Decency, science, democracy. They are all on the ballot. Who we are as a nation. What we stand for. And, most importantly, who we want to be. That's all on the ballot. And the choice could not be clearer. No rhetoric is needed," he said.
Biden said that as president, the first step he will take will be to get control of the coronavirus that has ruined so many lives.The US is the worst-hit nation with over 170,000 people dead and over five million people affected by the coronavirus pandemic.