The constant, upbeat intensity. The homespun catchphrases, like “B.Y.O.G.” — which stands for “Bring Your Own Guts.” (T-shirts are available.) The locker-room dance craze that’s sweeping the nation known as “The Dab” — not actually named for him, but he has made it so popular he probably could lay claim. Or admit responsibility.

It would be easy to dismiss the fountainhead of all this grits and grin craziness, Clemson coach Dabo Swinney, as the deliberate image-crafting of a football coach with ulterior motives.

But as surprising as it may seem, what you see with William Christopher “Dabo” Swinney is what he is.

No pretense, and certainly no filter.

“I’ve worked for two people in my time with that kind of attitude: Jim Valvano (the late North Carolina State coach and athletic director) and coach Swinney,” Clemson offensive line coach Robbie Caldwell said. “People thought (Valvano) put on a show for the cameras, but he was like that every day. Coach Swinney, even more so.

“He says, ‘If you can’t dream it, you can’t do it.’ The kids love him. He has fun with them. He’s competitive. He’ll kick field goals with them, shoot basketballs with them, whatever. It’s fun to be around. It’s fun to go to work every day. He lets you coach and holds you accountable when you should be.”

Swinney was already at Clemson when Dan Radakovich arrived to become the school’s athletic director after six years at Georgia Tech.

The former LSU senior associate athletic director had never met anyone quite like Swinney, either.

“There are days when things aren’t going well for a lot of different reasons,” Radakovich said. “If I’m having one of those days and I bump into Dabo at practice or go to his office, immediately things are better. He is the most positive person I’ve ever met.

“If you put him and Norman Vincent Peale in a room, I don’t know who would be happier.”

It’s easy to perceive Swinney as a lightweight, a charming fool, especially going against straight-laced, all-business Alabama coach Nick Saban in Monday night’s College Football Playoff national championship game.

But he makes no apologies for who he is or the image he projects to the world.

“Is that against the rules?” Swinney replied at Saturday’s CFP media day when someone asked whether he and his team were having fun. “That question, right there, is what’s wrong with society. I mean, it’s like a big deal if somebody enjoys what they do.

“Like we’re supposed to be miserable going through this. I don’t understand that.”

If anyone had reason to be miserable, it would have been Swinney in his younger days.

When his older brother Tripp was 16, he was involved in a serious car accident that left him in a coma. When Tripp, the brother who gave Dabo his nickname because as a toddler he couldn’t quite pronounce “That Boy,” awoke, his personality had changed. He has been through a string of personal problems, including an arrest in Florida last week for stalking and harassing his estranged wife.

Swinney’s father, Ervil, ran his own hardware store, but the business went bad when Dabo was in high school. His father started drinking and became abusive. The Swinneys divorced.

Eventually, Dabo’s mother and her three sons were evicted from a condominium they were living in because they couldn’t pay the rent. His mother lived with him for three years in his apartment as he pursued a walk-on football career at Alabama. He was a wide receiver on Alabama’s 1992 national championship team coached by Gene Stallings.

Stallings eventually made him an assistant coach, a position Swinney kept when Mike Dubose took over after Stallings’ retirement. But Dubose, another former Alabama player, and his entire staff were fired in 2000, forcing Swinney to leave coaching and take a job in commercial real estate.

In 2003, Swinney got back in the game when Tommy Bowden hired him to coach wide receivers at Clemson. Bowden, too, was fired midway through the 2008 season, and Swinney was named interim coach. Like the dogged former Alabama walk-on who eventually earned a scholarship, Swinney got the head coaching job full-time and never left.

Now, like another former Bama player and assistant, Danny Ford, he will try to lead Clemson to the national championship. And like Ford, he has to do it with an undefeated team playing the underdog to a bigger-name opponent: Clemson beat Nebraska 22-15 in the 1982 Orange Bowl.

Swinney said his team is trying to “slay the dragon,” a dragon he helped build once long ago. But, naturally, he couldn’t be happier about his circumstances, even turning the fact that his 14-0 Tigers are the underdog in his favor.

“I don’t care who we’re playing,” he said. “It would be gratifying to beat anybody for the national championship. That’s what we’re working for.

“Hopefully it’s Monday night. But if it’s not, we’re going to be right back here gathered up again somewhere. Because we’re not going away. We have a program that’s built to stay in the hunt.”

Of that, Swinney is positive.