An emotional high point came when Beau -- Delaware's attorney general, who is deploying to Iraq in October -- described the days after a car crash killed his mother and sister.
"One of my earliest memories was being in that hospital, Dad always at our side," Beau Biden said. "We, not the Senate, were all he cared about. He decided not to take the oath of office. He said, 'Delaware can get another senator, but my boys can't get another father.' However, great men like Ted Kennedy, Mike Mansfield, Hubert Humphrey -- men who had been tested themselves -- convinced him to serve."
Tears rolling down her face, Michelle Obama dabbed her eyes with a tissue throughout Beau and Joe Biden's speeches.
Members of the crowd were on their feet cheering when Biden took the stage and said, "Yes, yes, I accept your nomination!"
He reminded voters of his working class background in Scranton, Pa., and Wilmington, Del.
"Barack Obama and I took very different journeys to this destination, but we share a common story," he said. "Mine began in Scranton, Pa., and then Wilmington, Del., with a dad who fell on hard economic times, but who always told me, 'Champ, when you get knocked down, get up. Get up.'"
Biden told how his mother helped him through a stuttering problem as a child.
"My mother's creed is America's creed: No one is better than you. You are everyone's equal, and everyone is equal to you," Biden said.
Then Biden launched into an aggressive assault on McCain, playing the attack role of vice presidential candidates in the past.
"Almost every night, I take the train home to Wilmington, sometimes very late," Biden said. "As I look out the window at the homes we pass, I can almost hear what they're talking about at the kitchen table after they put the kids to bed."
Biden said millions of Americans are asking questions about their economic security.
"That's the America that George Bush has left us, and that's the future George, excuse me, John McCain ... will give us -- Freudian slip! Freudian slip," he said.
"As we gather here tonight, our country is less secure and more isolated than at any time in recent history," he said. "The Bush-McCain foreign policy has dug us into a very deep hole with very few friends to help us climb out."
Contrasting Obama and McCain on foreign policy, Biden said, "The choice in this election is clear. These times require more than a good soldier; they require a wise leader, a leader who can deliver change -- the change everybody knows we need. Barack Obama will deliver that change."
"Now, after six long years, the Bush administration and the Iraqi government are on the verge of setting a date to bring our troops home," Biden said, "John McCain was wrong. Barack Obama was right."
"This is his time, this is our time," Biden added. "God bless America and protect our troops!"
While all the party unity stagecraft was carefully planned, it was a speech tonight by former President Bill Clinton that threatened to remind voters of just how divided the party was during the bitter and lengthy primary campaign.
When the former president walked on stage Wednesday night, the crowd erupted into such wild applause that he asked them to stop.
"I love this, but we have important work to do tonight," he said after basking in the glow of the applause.
"First of all," he said, "I am honored to be here tonight to support Barack Obama."