And over his first three seasons in charge, two-thirds of the Notre Dame football team developed at a rate befitting a champion.
The defense has evolved from one of the worst in program history under the prior regime to among the nation's best.
The offense, behind a reborn running game, produced as many rushing touchdowns in the last two seasons, 48, than it had in the previous four prior to Kelly's arrival (49), averaging a 16-season high 4.9 yards per carry.
Then there's the Irish special teams, which in 2012 across the board, were anything but.
The kick return unit ranked 93rd; their coverage counterparts 77th. The punt coverage group was solid, ranking 40th, or just inside college football's top third, but the punt return team? 115th -- yes somehow worse than previous seasons that already served as a program punchline. And worrisome fumbles and muffs joined the late-season fray, to boot.
Even kicker Kyle Brindza was more clutch than consistent, missing eight kicks (the most at Notre Dame since 2008), while attempting a program record 31 and making a record 23. His touchback total of 26 was matched or bettered by roughly half the kickers in the college game (58 of the remaining 119 teams).
While Kelly and his staff could certainly live with a repeat overall performance by Brindza, especially in late-game situations, the rest of the specialty units are in need of resuscitation.
Enter Alabama, and more lessons learned.
"Here's what I know," said Kelly following his team's first spring practice. "Standing on the sideline for the national championship game, we're ready to kick off and Alabama has 11 starters on kickoff return. Kickoff return. Nobody wants to be on kickoff return.
"So the emphasis for us in this spring is to (have special teamers) really embrace their roles. I want starters to be part of our special teams units. The spring is really for us to integrate frontline guys in ST. And that kind of decision has to come from me. So I‘ve made that, and we're going about it in the spring to really put our best players on ST.
"Every single position is going to have the best players that we can get out there. We're going to make them compete for those positions."
Asked what prevented that practice -- one not exactly revolutionary -- in the past, Kelly offered. "Depth, injuries. You have guys running down there that are so central and critical (if they're starters). Now that we've been able to build some depth on both sides of the ball, I believe we can move more toward getting our front line guys out there."
May the Best Men WinRocket Ismail was on the Notre Dame punt team as an All-Amercian in both 1989 and 1990 -- not as its regular returner, mind you -- but as a speed demon looking to block punts.
First-team All-America cornerback Shane Walton was a "ranger" for the 2002 squad under Tyrone Willingham. He had no viable backup, but Notre Dame needed him to shadow gunners on the opposing punt teams (the "ranger" is a cornerback covering the punt team's player on the outside of the formation.)
And when teams kicked short to Lou Holtz's Irish to avoid Ismail the kick returner? The ball landed in the hands of the likes of future star running backs Lee Becton, Rodney Culver, and Dorsey Levens…not a backup tight end as it would have in 2012.
Depth allowed Holtz to use his best on special teams. (Todd Lyght and Pat Terrell covered punts as first- and second-round draft picks in 1989-90.) That's what Kelly believes he's finding more of in Year Four at his program.
"You'll need some depth. I think we're starting to accumulate some depth at those positions that we're not afraid to put a number of different guys out there (from scrimmage) if they need a blow on defense, or they need a blow on offense," he said. "As I told them, they're not going to take a blow on special teams. If you want to sit out a series or a few plays on defense, that's up to you. But we're going to get our personnel on the field as well in special teams."
The old adage "special teams is one-third of the game" has a chance to return to the equation in South Bend. With an offense expected to be far better in 2013, and a defense with but one major question mark, Kelly's specialty units might be the difference between a BCS appearance and BCS Championship.