In the speech, the two-term president recounted the beginnings of his relationship with the former Secretary of State, detailed her decades of advocacy work and extolled her drive in public service.
"In the spring of 1971 I met a girl," the 42nd president told the crowd in Philadelphia.
"She had thick blond hair, big glasses, wore no makeup and she exuded this sense of strength and self-possession that I found magnetic," he said.
"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 I really hoped that her choosing me and rejecting my advice to pursue her own career was a decision she would never regret," he said.
"She's been around a long time. She sure has. And she's sure been worth every single year she's put into making people's lives better. I can tell you this, if you were sitting where I'm sitting and you heard what I have heard at every dinner conversation, every lunch conversation on every long walk, you would say this woman has never been satisfied with the status quo in anything," he said. "She always wants to move the ball forward. That is just who she is."
And he described her as "the best darn change maker I ever met in my entire life."
"This is a really important point. This is a really important point for you to take out of your convention. If you believe in making change from the bottom up, if you believe the measure of change is how many people lives are bettered," he added.
Clinton addressed the differences between what was being said this week in Philadelphia and what the Republicans said in Cleveland last week.
“What's the difference in what I told you and what they said? How do you square it? You can't. One is real, the other is made up,” he said.
“You just have to decide -- you just have to decide which is which, my fellow Americans. The real one had done more positive change making before she was 30 than many public officials do in a lifetime in office.”
Clinton has been a regular speaker at Democratic conventions since at least 1980 and returned to the convention arena in 2012, when he gave a rousing 48-minute speech in support of President Obama's re-election. He was given the headlining spot on the third night of the 2012 convention -- one typically reserved for vice presidents.
The situation is understandably different this year.
"He thinks that it's important for other people to know the Secretary as well he does. So, tonight's speech will very much be a personal one for him," a Clinton aide told ABC.