After struggling to control his temper and his outbursts on the campaign trail in 2008, the former president has been a far more disciplined, supportive spouse on the campaign trail this time -- traveling across the country to campaign for his wife and carefully avoiding GOP nominee Donald Trump's provocations.
On Tuesday night, he delved deeply into her biography to cast her as change agent -- hinting that while she might not be as natural a politician, she has spent her life fighting to improve people's lives, particularly the lives of children and the disabled.
"She's the best darn change-maker I've ever met in my entire life. This is a really important point," Clinton said of his wife. "This woman has never been satisfied with the status quo ... She always wants to move the ball forward. That is just who she is."
At a time when many voters say they don't trust Hillary Clinton, her husband sought to soften her harder edges. He recalled how relentlessly he had pursued her, proposing to her three times before she accepted.
Bill Clinton's artful effort to humanize his wife, who sometimes comes off as robotic on the campaign trail and has struggled to win voters' trust, was met with enthusiastic cheers in the room. Before the former President's speech, several delegates said they were worried about the harsh negativity of the election and the seeming inability of Hillary Clinton to endear herself to voters.
The former President went to great lengths to do that for her.
"In the spring of 1971 I met a girl," he mused at the beginning of the speech -- as though Hillary Clinton was just any girl he might have courted in a long flowered skirt. He went on to note, in great detail, how she had repeatedly spurned his marriage proposals to focus on her work for poor children and education reform. He also described her as selfless, completely taken aback when he told her at one point that she would run for office. No one would ever vote for her, she told him laughing.
"I married my best friend. I was still in awe after more than four years of being around her at how smart and strong and loving and caring she was and really hoped that her choosing me and rejecting my advice to pursue her own career was a decision she would never regret," Bill Clinton said.
And his message seemed to resonate.
"I was very impressed, I think he made people understand who Hillary was from the time that he met her -- and how she fascinated him, and all the great things she has done for so many different groups. Most importantly how she put off making money to serve the people, the public," said Bobbie Richardson, a state legislator and delegate from North Carolina.
Richardson said she felt that for most of the American public that is a story that they don't know. "That's the beauty of it," she said. "As he said, people in Arkansas didn't know that she was the reason that they were benefiting from so many of these different programs."
Asked about the high level of distrust that many voters feel about Hillary Clinton, Richardson said testimonials like Bill's are exactly what is needed to change those perceptions.
"I think the more they hear about her between now and November 8th, the more they will realize that she's human. There were mistakes that she's made, but she's cleared of those mistakes," Richardson said. "Tonight we got the truth."
Richardson said she liked the wistful touch of romance that Bill Clinton added to his speech: "I think he was trying to show that he remembered what she looked like, and what she wore 40 years ago. I thought that was the beauty of how romance starts."
Clinton holds a much higher favorability rating than his wife. Among Democratic voters, 79% view him favorably.
The former president has turned into a frequent target for Trump, who has railed about the former president's personal life from the campaign trail.
"She's married to a man who is the worst abuser of women in the history of politics. She's married to a man who hurt many women," Trump said at a rally in Spokane, Washington. "And Hillary was an enabler and she treated these women horribly. Just remember this. And some of those women were destroyed not by him, but by the way Hillary Clinton treated them after everything went down."
Trump has also seized on Clinton-era policies, going after NAFTA, which Trump has vowed to renegotiate.
"She doesn't understand trade," Trump said. "Her husband signed perhaps in the history of the world the single worst trade deal ever done."
Bill Clinton has also faced scrutiny over his legislative record directly from voters on the campaign trail. In April he was confronted at a campaign event for his wife in Philadelphia by Black Lives Matter activists over his administration's 1994 crime bill.
"You are defending the people who killed the lives you say matter," Clinton pushed back from the podium.
On the campaign trail, Hillary Clinton has at times tried to distance herself from her husband, repeating regularly that she is running on her own record, not "running for her husband's third term."
But she has had to clean up after him at times -- most recently in the aftermath of Bill Clinton's private, impromptu meeting with Attorney General Loretta Lynch at the Phoenix airport in June. The meeting was widely criticized given that the attorney general was overseeing the investigation into Hillary Clinton's use of a private email server while secretary of state.
"I think, you know, hindsight is 20/20," Hillary Clinton said of the meeting in an interview with NBC News. "Both the attorney general and my husband have said they wouldn't do it again, even though it was from all accounts that I have heard and seen, an exchange of pleasantries. But obviously no one wants to see any untoward conclusions drawn, and they've said, you know, they would not do it again."
Still, Hillary Clinton sees her husband as an asset.
She has pledged to give him a role in a potential second Clinton administration dealing with the economy, trying to capitalize on her husband's economic record while he was in the White House.
"I'm going to put (him) in charge of revitalizing the economy," Clinton said in Fort Mitchell, Kentucky, this May. "You know he knows how to do it, especially in places like coal country and inner cities and other parts of our country that have really been left out."
Bill Clinton would still be entering uncharted waters should the White House be helmed by his wife, becoming the first man to fill the role of president's spouse.
Hillary Clinton has suggested that in lieu of first lady he could be called "first dude, the first mate, the first gentlemen."
He has suggested "first laddie."
"I don't know, I don't really know because it'd be such a precedent," he said of a potential title. "I don't care what I'm called, it's more about what I'm called to do."