Joe Biden promised to restore the "soul of America" and deliver the nation from "darkness" as he accepted the Democratic nomination for president Thursday night, a crowning achievement in Biden's five decades in politics where he was counted out more than once.

Speaking from Wilmington, Del., Biden said President Trump has failed in his basic duties to protect Americans as he pledged to get a handle on the coronavirus that has killed more than 170,000 Americans and put the country on an economic downward spiral.

Democratic presidential candidate former Vice President Joe Biden speaks during the fourth day of the Democratic National Convention, Thursday, Aug. 20, 2020, at the Chase Center in Wilmington, Del. (AP Photo/Andrew Harnik)

HUNTER BIDEN MAKES RARE APPEARANCE WITH DNC REMARKS

"Our current president is failed in his most basic duty to the nation. He's failed to protect us. He's failed to protect America, and my fellow Americans, that is unforgivable," Biden said. "As president, I'll make you a promise: I'll protect Americans. I will defend us from every attack -- seen and unseen -- always, without exception, every time."

Biden, the three-time presidential candidate who was written off in early 2020 after losing both Iowa and New Hampshire, said he's the candidate who can lead the nation through the dark times. He cited four major crises: COVID-19, the economic downturn, climate change and the demands for racial justice from communities who "know the injustice of a knee on the neck."

He blamed Trump for stoking anger and divisions in America, and pledged to bring the country back into the "light."

"I give you my word: If you entrust me with the presidency. I will draw on the best of us, not the worst. I'll be an ally of the light, not the darkness," Biden said.

Democratic presidential candidate former Vice President Joe Biden, and his wife Jill Biden, watch fireworks with Democratic vice presidential candidate Sen. Kamala Harris, D-Calif., and her husband Doug Emhoff, during the fourth day of the Democratic National Convention, Thursday, Aug. 20, 2020, at the Chase Center in Wilmington, Del. (AP Photo/Andrew Harnik)

He later closed, "Love is more powerful than hate, hope is more powerful than fear and light is more powerful than dark -- this is our moment, this is our mission."

The Biden family -- bonded by tragedy -- teed up the former vice president's biggest speech of his career. His grandchildren starred in a video highlighting their close bond to Biden. His two surviving children, Ashley and Hunter, honored their late brother Beau and talked of their father's strength through adversity. "He'll never let you down," Hunter said.

For four days, Democrats sought to drive home a message that Trump has proven he's incapable of leading the nation, and Biden will restore the dignity and humanity to the Oval Office as well as heal a nation grappling with the coronavirus pandemic, economic suffering and social unrest.

KAMALA HARRIS ACCEPTS HISTORIC VP NOMINATION, SAYS 'THERE IS NO VACCINE FOR RACISM'

"May history be able to say that the end of this chapter of American darkness began here, tonight as love and hope and light join in the battle for the soul of the nation -- and this is a battle we will win and we'll do it together," Biden said.

Trump gave a real-time reaction to Biden's speech on Twitter.

"In 47 years, Joe did none of the things of which he now speaks," Trump said. "He will never change, just words!"

Tim Murtaugh, Trump 2020 communications director, added: "Joe Biden is a twice-failed candidate for president and is, without question, a far worse candidate the third time around.”

The final night of the convention focused on Biden's long career of public service and the lives of Americans he's touched along the way, from military families to helping Brayden Harrington, a 13-year-old New Hampshire boy who struggles with stuttering as Biden did as a child.

Biden and Brayden Harrington (AP)

Supporters talked of how Biden's experience with grief allows him to care deeply for others in pain, and will even hand out his personal phone number to everyday Americans.

TEEN FOLLOWS BIDEN'S ADVICE ON LIVING WITH A STUTTER, DELIVERS ROUSING DNC SPEECH

"My family's grief mattered to him," said Amanda Litman, co-founder of Run for Something, whose family bonded with Biden over cancer. "Our entire country is grieving. We are all going through trauma, our next president needs to be the one helping us heal."

Biden's speech was the pinnacle of his nearly 50 years in politics. His ambitions started in Delaware in 1970 with local politics and then shifted to Washington with 36 years in the U.S. Senate and eight years as vice president.

His political career has been bookended by deep personal tragedy. Just as he won his first term to the Senate in 1972, his first wife, Neilia, and their 1-year-old daughter Naomi were killed in an auto accident in Delaware.

Ever since Biden was first sworn in as senator in 1973 at the Wilmington hospital that treated his injured sons, Beau, and Hunter, he became known as a tragic figure who persisted despite the heartbreak. He ran for president twice before in 1988 and 2008. The first run, at age 44, was marred by revelations of plagiarized speeches and exaggerations, including his law school record.

FILE: Sen. Joseph R. Biden Jr. (C) campaigning at an adult education center after announcing his bid for the 1988 Democratic presidential nomination. (Photo by Steve Liss/The LIFE Images Collection/Getty Images)

He tried again at age 64 touting his experience and stature in the Senate, but he didn't gain traction compared to challengers who had the potential to make history, then-Sen. Barack Obama and then-Sen. Hillary Clinton. The gaffe-prone Biden in 2007 described Obama in the New York Observer as "the first mainstream African-American who is articulate and bright and clean and a nice-looking guy."

The remark didn't, however, prevent Obama from tapping Biden as his vice president and relying on Biden for his foreign policy experience and longtime relationships on Capitol Hill. When Obama approached Biden for the job he framed the vice-presidential slot as "the capstone" of his long career. "Not the tombstone?" Biden joked, according to Newsweek.

Biden wanted a partnership. "I told him, 'The good news is, I'm 65 and you're not going to have to worry about my positioning myself to be president. The bad news is, I want to be part of the deal.'"

President-elect Obama announcing his national security team in 2008/AP

FILE: President-elect Obama announcing his national security team in 2008/AP

Biden mulled a third run for president as the Obama-Biden Administration came to close, but decided against it after suffering another tragedy, the 2015 death of his beloved son, Beau, who was following in his father's footsteps in politics before succumbing to brain cancer at age 46.

The convention featured a tribute to Beau Biden, a former soldier and Delaware Attorney General, and the impact he continues to make on his father. "Even though he is no longer with us, every day he still inspires the next president of the United States," the video said.

Now after three times at trying, Biden has his best shot yet of fulfilling his longtime dream of becoming president. He once ran for the White House hoping to be the youngest president since John F. Kennedy, but through an unlikely fate, his political career peaked in his golden years.

If he succeeds, he'll be 78 on Inauguration Day and the oldest president in United States history.

ANDREW YANG IN DNC SPEECH: ‘WE ARE IN A DEEP, DARK HOLE’

Helping him along the way are his former 2020 Democratic competitors. Biden got a big assist at the convention from former rivals including, Sen. Cory Booker, D-N.J., former South Bend Mayor Pete Buttigieg, Sen. Amy Klobuchar, D-Minn., Sen. Elizabeth Warren, D-Mass., former congressman Beto O'Rourke, Sen. Bernie Sanders, I-Vt., entrepreneur Andrew Yang and former New York City Mayor Mike Bloomberg.

They set aside their differences from the campaign trail and united around Biden in speeches and campaign videos that stressed the importance of defeating Trump for the sake of democracy.

"He has failed us," Booker said of Trump.

From left, Democratic presidential candidates, former New York City Mayor Mike Bloomberg, former South Bend Mayor Pete Buttigieg, Sen. Elizabeth Warren, D-Mass., Sen. Bernie Sanders, I-Vt., former Vice President Joe Biden, Sen. Amy Klobuchar, D-Minn., and businessman Tom Steyer participate in a Democratic presidential primary debate, Tuesday, Feb. 25, 2020, in Charleston, S.C. (AP Photo/Matt Rourke)

DNC DRIVE-IN: MORE THAN 100 CARS EXPECTED OUTSIDE CONVENTION FOR BIDEN, HARRIS’ POST-SPEECH WAVE

"In Joe Biden, you have a human being who is empathetic, who is honest, who is decent," Sanders said in a video message of the 2020 hopefuls dubbed "United We Stand."

Actress Julia Louis-Dreyfus dished up some comic relief as emcee of the convention's finale, capping off a star-studded four-day event that also featured John Legend, Kerry Washington, Jennifer Hudson, Common, Eva Longoria, Billie Eilish and more.

The coronavirus pandemic shut down plans for Biden to accept the nomination before a packed arena in Milwaukee. The closest Biden came to a crowd at the virtual convention were the cars parked outside the Chase Center in Wilmington to watch the keynote address on an outdoor screen for a DNC drive-in party.

TRUMP MOCKS BIDEN'S SCRANTON ROOTS AHEAD OF CONVENTION SPEECH: 'HE ABANDONED PENNSYLVANIA'

After the speech, Biden, wife Jill, running mate Sen. Kamala Harris and her husband Doug Emhoff all put on masks for a fireworks display in the parking lot.

"While I will be a Democratic candidate, I will be an American president," Biden said in his speech. "I will work as hard for those who didn't support me as I will for those who did. That's the job of a president. To represent all of us, not just our base or our party. This is not a partisan moment. This must be an American moment."