Thornton has a new attitude and even looks physically different as well.
"I had a great off-season, and I got a lot of extra work in the summer this season because I know how much I'll be counted on," he said. "I actually gained twenty pounds since last season."
They'll need him to step up to a leadership role after losing several seniors off last year's team.
"We have a bunch of young guys who can really play and we have two who have some experience from last year," he said. "We are going to be good. Coach tells us the defensive line sets the tempo for all of our practices, so its up to us to get after it each and every day."
This is a challenge he continues to embrace, one sign that he is maturing into the player everyone knows he could be. This is true not only for him, but also for teammate Rakeem Nunez.
"Rakeem did what he did last season and he really helps set the tone for us," he said. "He's ready now, he was born ready. He came out of High School ready, and him and I are going to be the guys in the middle for this defense."
He is excited to have the coaches he has this season, especially with a big focus on the defense.
"Coach Johnson and Coach West know defense, and it was Coach Johnson's scheme that beat Nebraska last season for South Carolina in the bowl game," he said. "We know we can do it too. He's defensive minded and we have to listen and pay attention and we can be really good."
Could this defense be even better this season than last?
"We can't compare ourselves to last season," he said. "It was a special year, we were able to put offense, defense, and special teams together. This is a new year, new team, and take each game one at a time.
"The defense we are in now opens up a lot of holes for us to make big plays. One thing that will make us great is that we have depth on the line. Anthony Wilson, Wil Freeman, Dalvin Craft, and Adam Williams are all going to be really good in the future.
"We have to show them the way, you know. I was once where they were and guys like Cordarro Law showed me the way. I took it upon myself to mature and be that player for these guys."
They taught Thornton that he can not take a play off even in practice. He's taken that to heart this season.
"We've done a lot of drills to start the season in practice this year," he said. "We do everything really hard and up tempo. I'm trying to set the pace for everyone.
"Coach Zo has been great because he keeps us going hard. He's not the kind of guy that will ream you out in front of everyone else. He'll take you to the side and show you what you are doing wrong or how you can do it better. I like that about him."
The next challenge is Nebraska, and one big Thornton says the defense will be ready for.
"Its a big stage, a big opportunity, and we have to get up for that," he said. "It is an opportunity for us to show how good of a team we are. We want the nation to see what Southern Miss is all about.
"We've been watching film on them since the spring. I can promise you, we'll be ready."