If LSU beats Notre Dame on Tuesday in the Music City Bowl, the Tigers will gather in front of the LSU band and sing the alma mater.

It’s a tradition started by coach Les Miles after he arrived at LSU in 2005.

If Miles and the Tigers are singing, it’s a good bet that Tre’ Sullivan’s smiling face will be somewhere in the vicinity of the LSU coach.

That’s one of the Tigers’ traditions, too.

“I don’t know, man,” Sullivan said. “It’s not like we plan it or anything. It just so happens that whenever I’m next to coach Miles, there’s a camera right there. They’re following him. I’m just happy to be there.”

As Sullivan explained his passion for paparazzi moments, he was smiling. He’s always smiling, whether there’s a camera around or not.

“He’s a good dude,” linebacker Kendell Beckwith said. “He’s always trying to keep up a positive vibe and keep everyone focused.”

Sullivan said that’s just his way.

“My teammates and coaches love me for it,” Sullivan said, grinning broadly. “If they see me not smiling they’re like, ‘What’s wrong?’

“I guess it’s the way I was raised. My mom told me if you don’t like something, change it. But do it with a smile on your face. People don’t have to know the pain you’re going through.”

Sullivan has had an extra reason to smile this season.

A four-sport athlete at Donaldsonville High School — and the son of Donaldsonville mayor Leroy Sullivan — Tre’ Sullivan came to LSU as a walk-on but was awarded a scholarship by Miles in June.

“Coach (Sam) Nader called me and said coach Miles wanted to meet with me,” Sullivan recalled. “He called me in and told me I deserved to be on scholarship, that I was one of the hardest-working players he’d ever been around.”

Fellow senior walk-on Chris LaBorde, a wide receiver from Lafayette, admitted he was a bit jealous of Sullivan at first.

It was an emotion that was short-lived.

“There is a little bit of ‘I wish it was me,’” LaBorde said. “But at the same time, I was so happy for him. He deserved it more than anyone. If that’s who the coaches felt deserved it, I completely agree with that.”

Sullivan said he felt he earned a scholarship for all of LSU”s walk-ons.

“It’s bigger than a scholarship,” he said. “It shows an underdog can make it. A little fish can survive in a big pond.”

It’s a sentiment Miles can appreciate.

“Our scout team is a special group of guys,” Miles said. “They’re guys who will have their degree, but their contribution is not necessarily game day. It’s in practice.

“Guy like Tre’ Sullivan give a very significant advantage to LSU.”

The walk-on’s existence on a college football team isn’t an easy one.

They practice with little if any hope of ever making it into an actual game, with no scholarship aid like the other more highly recruited former prep stars in the locker room.

Sullivan said he’s played in two games as a Tiger; LaBorde estimates he’s made it onto the field for five or six snaps total.

“That’s two more games than people thought I’d play in,” Sullivan said. “I’m thankful for everything. If I could do it all over again, I wouldn’t change a thing.”

Mostly the role of a walk-on is to help prepare the scholarship players for that week’s game as a member of the scout squad.

In LSU’s run up to Tuesday’s Music City Bowl against Notre Dame (2 p.m., ESPN), LaBorde is playing the role of Irish wide receiver William Fuller. Sullivan is cast in the role of Notre Dame starting cornerback Cody Riggs.

Like the most famous walk-on of them all, Notre Dame’s Daniel “Rudy” Ruettiger, Sullivan said he treats every practice like it’s an actual game.

“It’s not certain I’m going to get in the game on Saturday,” Sullivan said. “So Monday through Thursday has to be my game. I come with the game face and the same spirit they see on the sideline at the game.”

Sullivan could have played at another school, another school in Louisiana, but he said it wouldn’t have meant as much to him.

“My goal coming out of high school was not just playing college football, but to play at LSU,” he said. “I’m proud of where I’m from. Putting LSU on my chest is big.”

Part of the reward for the walk-ons — and former walk-ons like Sullivan — in honor of their hard work throughout the season is a chance to dress out for the bowl game.

For Sullivan, it’s one last chance to leave his mark on the program.

“The goal is to keep the guys focused, especially the young guys,” said Sullivan, who graduated last week in business and plans to begin pursuing an MBA next fall. “Practicing without a game that Saturday, you can get sidetracked.

“I’m trying to instill in the young guys a sense of how things are done, especially the walk-ons,” he said. “I want to let them know you don’t always have to be a walk-on. You can be a scholarship guy.

“I want to be remembered as the guy who came as an underdog but helped build the program. Like (special teams) coach (Bradley Dale) Peveto tells us, try to make a difference. Every day I ask myself, ‘Did I make a difference today? Did I make myself or someone else better?’”

After the Music City Bowl, Sullivan will have only one task left to perform:

Finding someone to sing the alma mater with Miles after another LSU victory.

-- Follow Scott Rabalais on Twitter: @RabalaisAdv.