Mike Slive is a unique figure in college athletics.

He isn’t physically imposing. He’s never known to raise his voice to make himself heard. And, in an increasingly rare trait in the sports world, never puts himself in a compromising position through his word or deed.

In fact, it would be easy to underestimate Slive completely — but probably only once.

“When he first started it’s was like ‘Who is this guy in the SEC,’ ” said Wright Waters, executive director of the Football Bowl Association and former commissioner of the Sun Belt Conference. “He was always very quiet, and very thoughtful.”

In a dozen years as Southeastern Conference commissioner, Slive has been the embodiment of the phrase made famous by the larger-than-life Teddy Roosevelt more than 100 years ago:

“Speak softly and carry a big stick; you will go far.”

Slive’s big stick has been the SEC itself. The conference that under his direction has won 67 national championships, most famously (or infamously if you live outside the SEC footprint that Slive himself expanded) seven straight BCS football titles from 2006-12.

It was the SEC’s big stick in the form of LSU and Alabama playing each other for the 2011 BCS championship, arguably the high-water mark of the Slive era, that finally cleared the field for the creation of the College Football Playoff. There was Slive, leading the charge across that field, getting the kind of playoff that best suited the SEC (being a conference champion isn’t a requirement to be in the final four).

Earlier this year, Slive turned that big stick into a sword and rattled it, lobbying an implied threat at the NCAA Division I membership outside the power five conferences (and Notre Dame, always Notre Dame). He basically said to the rest of the NCAA, “give us more autonomy to make our own rules that best suit us, or we will create a new NCAA division — or a new NCAA.”

“I’m somewhat optimistic it will pass,” Slive said in May at the SEC Spring Meeting.

“It is time. I do believe this is a historic moment. If we don’t seize the moment, we will be making a mistake.”

The moment was seized by the rest of the NCAA membership. Autonomy is being created for the power five conferences as you read this. Waters believes the move Slive pushed for will help college sports in general.

“One of the great things about Mike was that he always saw a bigger picture,” Waters said. “That’s a trap so many people fall into — making it a competition and they lose sight of what’s best for intercollegiate athletics.

“Mike always kept a broad view, because he was big-picture guy. I used to tell him what was good for the SEC was good for the Sun Belt Conference, and I meant it.”

Speaking and acting so boldly isn’t always Slive’s style. Sometimes he has been want to wait, even to the point of being criticized for doing so, while major college athletics-shaping events happened around him.

The Big Ten started its own TV network in 2007. Slive chose to create the SEC Network this year, when he got ESPN to swallow the startup costs. The network could be worth upwards of $35 million a year to SEC members and already has as many viewers as the older BTN.

When the conference realignment craze started, the SEC looked like it was going to get shut out. Then Slive pulled in Texas A&M and Missouri. The former looked like a good fit, the latter not so much, but so many more eyes from Houston to Dallas to St. Louis to Kansas City are watching.

Now Slive has announced, at age 74, with a recurrence of prostate cancer that he once fought back like a rival league in the late 1990s, that he’s stepping down July 31. He leaves as the best, most proactive, most capable commissioner the SEC has ever had.

No, he didn’t get everything right. Permanent cross-divisional games are still in place, still creating the same competitive imbalances in scheduling they have for years.

But even a foe on the subject like Les Miles can appreciate the Age of Slive and what it has meant to the SEC.

“We’ve won national championships under his direction in multiple sports,” said Miles, including his with LSU football in 2007. “Revenue at all the schools has gone up. He’s put us in position to have the SEC Network. He’s positioned us well in the bowl structure. He’s really taken the lead in autonomy of the big five conferences … so they can have a greater say about the rules. He will certainly be missed.

“The only thing he didn’t address was permanent crossover partners. But nobody’s perfect.”

Landing the perfect successor to Slive will be almost impossible.