Taking her place in history on Tuesday evening, Hillary Clinton became the first woman to lead a major U.S. political party toward the White House, a triumphant moment for Democrats to relish before plunging into a bruising general election against Republican Donald Trump.
Delegates erupted in cheers as Ms. Clinton's primary rival, Bernie Sanders, made it official and unanimous – an important show of unity for a party trying to heal deep divisions.
"I move that Hillary Clinton be selected as the nominee of the Democratic Party for president of the United States," Mr. Sanders declared, asking that it be by acclamation.
The arena exploded in cheers as a sea of delegates waved multicolored signs with Clinton's "H" campaign logo. Mr. Sanders, his lips pressed together, hugged his wife, Jane, and waved briefly to the crowd before heading out of the hall.
But elsewhere on the floor, several dozen Sanders delegates paraded off in a coordinated demonstration against Ms. Clinton's nomination.
Several of them said beforehand that they were attending their first Democratic convention and felt no party loyalty or compulsion to fall in line behind the former secretary of state, whom they described as insufficiently progressive on new banking regulations, a $15 minimum wage, a ban on fracking and other issues championed by Mr. Sanders, a self-described democratic socialist.
"I'm just not there yet in terms of supporting Hillary, because her words are only her words, and I don't fully trust that she'll act on our agenda," said Ingrid Olson, 38, a delegate from Iowa, where Sanders narrowly lost the first-in-the-nation caucuses in February.
Ms. Olson argued that party unity was a myth, saying that some Clinton campaign officials canvassing the floor had banned the homemade signs of Sanders supporters but handed out ones that championed Clinton.
The final delegate count was 2,842 for Clinton, 1,865 for Sanders and 56 "no votes" before Mr. Sanders urged unanimity in the fight against Mr. Trump.
His action was a striking parallel to the role Ms. Clinton played eight years ago, when she stepped to the microphone on the convention floor in support of her former rival, Barack Obama.
And it was a dramatic contrast to Republican Senator Ted Cruz's refusal last week to endorse Mr. Trump in similar circumstances after finishing a distant second in a GOP primary campaign that was even more bitter than the Democrats' race.
Earlier, Maryland Senator Barbara Mikulski formally nominated Ms. Clinton earlier Tuesday, saying she was acting on behalf of "all women who have broken down barriers for others."
"Yes, we do break barriers. I broke a barrier when I became the first Democratic woman elected to the Senate in her own right," Ms. Mikulski said. "So it is with a full heart that I'm here today to nominate Hillary Clinton to be the first woman president."
Ms. Clinton's campaign hopes Tuesday's scheduled speakers about her achievements, coupled with personal stories and praise, can chip away at the deep distrust many voters, including some Democrats, have of the former secretary of state, senator and first lady.
Three hours of speakers were chosen to highlight issues she has championed for years, including health care and advocacy for children and families.
Former president Bill Clinton used his legendary speaking prowess to paint a loving portrait of Ms. Clinton as a wife, mother and activist who has succeeded at every level, both personal and professional.
He talked at length to delegates about his early courtship of Ms. Clinton, their daughter, their life and their work together on a variety of liberal causes, including civil rights and opposition to the Vietnam War.
"I married my best friend," he said to loud applause after telling delegates she had rejected his marriage proposals twice before accepting the third.
Mr. Clinton accused his wife's Republican rivals of creating a "cartoon" version of his wife to attack because they can't challenge her real credentials.
"Hillary will make us stronger together," he said as he urged the party to rally around his wife's candidacy.
Earlier in the evening, a group of women who have lost children to gun violence or after contact with police took the stage to applause and chants of "black lives matter".
Known as the Mothers of the Movement, the group includes Sybrina Fulton, whose 17-year-old son Trayvon Martin was killed by a neighbourhood watch volunteer in 2012.
"Hillary Clinton has the compassion and understanding to support grieving mothers," Ms. Fulton said. "She has the courage to lead the fight for common sense gun legislation."
Also taking the stage Tuesday were former U.S. Attorney General Eric Holder and Pittsburgh Chief of Police Cameron McLay, who said it is possible "to respect and support our police while at the same time pushing for these important criminal justice reforms."
Clinton has made gun safety one of the foundations of her presidential campaign, vowing to overcome the legendary resistance of gun-rights advocates and their GOP allies to push for expanded criminal background checks and a renewal of a ban on assault weapons.
By night's end, the Clinton campaign hoped to have moved past the dissent that somewhat tarnished the convention's opening day. Supporters of Mr. Sanders, Ms. Clinton's primary rival, repeatedly interrupted the proceedings with boos and chants of "Bernie."
Mr. Sanders has implored his supporters to not protest during the convention, but he's struggled to control his energized backers. Several hundred people gathered at Philadelphia's City Hall under a blazing sun Tuesday, chanting "Bernie or bust."
The morning after his rousing endorsement of Ms. Clinton at the convention, Mr. Sanders himself was booed as he arrived for a breakfast with California delegates.
"It is easy to boo," Mr. Sanders said in response. "But it is harder to look your kids in the face who would be living under a Donald Trump presidency."
Mr. Trump cheered the disruptions from the campaign trail. In North Carolina on Tuesday, he told a convention of the Veterans of Foreign Wars that "our politicians have totally failed you."
When Mr. Trump mentioned Ms. Clinton's name, the group answered with shouts of "Lock her up!" – an echo of the chants at last week's Republican convention.
Mr. Trump has been a frequent target at the Democratic gathering, where several videos featured his comments about women and the disabled, and tried to discredit the real estate mogul's business record. But unlike the GOP convention in Cleveland, Democratic speakers made a concerted effort to mix the criticism with upbeat remarks about the country and their party.