WALTHAM, Mass. -- Boston Celtics president of basketball operations Danny Ainge and team owner Steven Pagliuca were sitting courtside at the 2010 NCAA men's basketball championship game when Ainge noted that the best coach in college basketball was on the sideline.
Pagliuca, a Duke alum and Blue Devils superfan, thought Ainge was talking about coach Mike Krzyzewski. Ainge, though, was hinting at Butler coach Brad Stevens.
"I was secretly rooting for Butler to win the national championship," explained Ainge. "So [Pagliuca] had a big argument with me, saying, 'Coach K is the best coach of all time and history.' Part of it was I believed [Stevens was the best], but part of it was just to get under Pags' skin."
Three years later, Pagliuca has to admit he's a pretty big fan of Stevens (the fact that the Blue Devils won that game makes it a little easier). Ainge and Pagliuca were two of Boston's brass who flanked Stevens when he was introduced as the 17th head coach in Celtics history on Friday at the team's training center.
The 36-year-old Stevens will be tasked with the challenge of leading a young team through a rebuilding process, but 18s decorated every scoreboard in the gymnasium, a reference to the team's quest for its next championship banner.
Stevens said Friday he was "absolutely humbled" by the opportunity to coach the Celtics.
"One of the things that I am so thrilled about is working at a place that has such high standards," Stevens said, "and places such a value on culture."
Stevens spent part of the morning diving into film of his new team. His wife/agent, Tracy, joked that it's the biggest smile he's had all week after an emotional decision to make the jump to the pro level.
Stevens has spent the past six years coaching at Butler, leading the Bulldogs to back-to-back national championship games in 2010 and '11, a remarkable feat for a Horizon League team. He has a career winning percentage of .772 and never won fewer than 22 games in a season. He has no NBA experience.
"Anytime you have an opportunity for personal growth like this, those are things I really latch onto," said Stevens. "I know there's a lot of growing ahead, I'm the first to admit that. I've got a long way to go, I've got a lot to learn."
Stevens replaces Doc Rivers, who was on the Boston bench for nine seasons before leaving for the Los Angeles Clippers last week. Also gone from the Celtics are veterans Kevin Garnett, Paul Pierce and Jason Terry, who were dealt to Brooklyn in a deal that netted Boston a bevy of role players and three first-round draft picks.
Ainge said at Friday's introduction that his "first phone call" after Rivers' departure was to Stevens.
"Brad was my first choice," Ainge said. "I have watched and admired his poise, his intelligence, his teams, their effort, their execution under pressure. I've always looked at him the last few years as a guy that was a great candidate to be a head coach [in the NBA], never really thinking it was going to be this soon in Celtics history, but [he] is a guy that I have targeted for a long time as a potential great head coach."
Stevens is the youngest coach in the NBA.
A source close to the Celtics confirmed that Stevens' deal is for six years and $22 million.
He takes over a team that is three seasons removed from an appearance in the NBA Finals. The Celtics won their unprecedented 17th championship in 2008. But with Garnett and Pierce showing signs of slowing down in this year's playoffs, when Boston was eliminated by the New York Knicks in the first round, Ainge has decided to rebuild.
"We all know what we are about to embark on," Ainge said, "and he will have great support from ownership and from management. Yes, there will be transition, from the college game to the NBA game, but we will give him the support that he needs to make that transition fast. He's a very smart guy."
The surprise move to hire Stevens turns the tradition-bound franchise over to a mentor who is younger than Garnett and who wasn't yet born when Bill Russell won his 11th NBA championship in 1969 (or when John Havlicek added two more in the 1970s). It's the first time the Celtics have hired a college coach since Rick Pitino in 1997, and Stevens is their first coach with no NBA experience of any kind since Alvin "Doggie" Julian gave way to Red Auerbach in 1950.
A source with direct knowledge of the situation told ESPN.com's Andy Katz that the Celtics contacted Stevens a week ago. The two sides had phone conversations, and the Celtics were waiting for Stevens to say yes. Ainge and the Celtics' ownership group flew to Indianapolis on Wednesday morning for their only in-person meeting with Stevens, and he accepted the job there.
It was on the tarmac in Indianapolis on Wednesday that, so smitten by their in-person interview with Stevens and his family, Pagliuca and co-owner Wyc Grousbeck pleaded with Ainge to stay behind in hopes of sealing a commitment from Stevens.
"Wyc and Pags, they loved him so much, because they had never met him," said Ainge. "It's always better when the owners want him even worse or more than you do. They almost didn't let me get on the plane."
Information from ESPN.com's Andy Katz and Jeff Goodman and The Associated Press was used in this report.