If not for a push from Mike Price 23 years ago, Sumlin might have ended up focused more on how to stop offenses rather than creating them. Sumlin, after all, was a college linebacker and began his coaching career on that side of the ball.
Price, the UTEP coach who is retiring after this season, gave Sumlin his first job as a graduate assistant at Washington State. He summoned him to his office one day and told him he'd be coaching Washington State's junior varsity team as it played area junior colleges—and that he needed to learn the offense.
Sumlin was confused and asked Price why.
"You need to move the offense and you need to learn what we're doing here," he said Price told him. "Because if you learn what we're doing here with this offense—it's a little bit different. You'll have a job the rest of your life somewhere."
Sumlin was sold.
"I said: 'That's sound pretty good to me,'" Sumlin said with a smile.
Sumlin enjoyed his foray into offense and never had a job on defense again. From 1991-2007, he made various stops as an assistant working mostly as a receivers coach and then offensive coordinator. In 2008, he nabbed his first head coaching job at Houston, inheriting a quarterback named Case Keenum, and the pair used his high-flying offense to help the Cougars to heights they hadn't reached in decades.
Keenum, who became the Bowl Subdivision's all-time career passing leader under Sumlin's watch, was stumped to pick just one reason why his former coach has been so successful.
"There's probably a million reasons why," Keenum said. "He's a great guy. He comes on strong at first, but once you get to know him he's a players' coach. I loved him. I loved playing for him. I don't know why you wouldn't."
That, people say, is a big reason why Sumlin has done so well in his first season at Texas A&M. The nine wins he has led the Aggies to this season are already a record for a first-year coach at the school, and they still have two games left. A win over Missouri on Saturday will give Texas A&M its first 10-win season since 1998.
"I had no doubt that he'd be successful and no doubt that those guys would do a great job of coaching," Keenum said. "What maybe has been a surprise is how well the players have adapted to him. I think everybody knows how difficult it is to go into a program first year as a head coach and change things and change the way little things are done."
Sumlin gives much of the credit for the team buying into his plans to the seniors who led the way. The group also helped the Aggies focus when their opener was postponed because of a hurricane, forcing the them to play their entire schedule without a break.
"The biggest thing to me is how this team has come together and accepted this coaching staff from the beginning," Sumlin said. "There was a lot of tension then to now where there is some ease in talking with guys about a lot of things that have nothing to do with football. That's what makes coaching a lot of fun."
Price didn't have a grand plan when he pushed Sumlin into offensive work. He just thought it would make him a more well-rounded coach.
"I wanted him to master both sides of the ball," Price said in an interview with The Associated Press. "What we were doing at the time was new and hot and people were picking it up. It was smart for him to do that and it made sense because he is a smart guy."
Price said Sumlin jumped into the task with the same enthusiasm he brought to everything he asked him to do back then. His ability to catch on to the offense quickly wasn't surprising to Price.
"He's just got success written all over him," Price said. "He's charming. He's funny. He's bright. He's hardworking. He's nice to people. He's a good person to his coaches and he's a good father and a good husband and he treats people with dignity and respect."
There was a time when Sumlin wouldn't have imagined being a coach, even though his father, William Sumlin, was a high school coach when Kevin was young.
"My dad didn't want me to be a coach because he was a coach," Sumlin said. "Anybody who's been a coach would probably say: 'No you don't want your kid to be a coach.'"
He had career plans that would have taken him far away from the football field.
"I thought about being a lot of different things. At one point I was going to go to law school. That didn't work out. Probably should have done that though instead of dealing with you guys," he said, laughing as he referred to the media.
But after he began his coaching career with Price, he never looked back. His ascent has been helped by the no-nonsense attitude he has with players.
"He's going to tell you how it is," Texas A&M senior defensive lineman Spencer Nealy said. "I don't like people who beat around the bush. Coach Sumlin, from Day 1, if you were playing bad he was going to tell you you're playing bad."
To that end, he always looks for those teaching moments.
One of Keenum's fondest memories of Sumlin came when the quarterback tossed an interception in the end zone that cost Houston a game. Keenum knew everyone was unhappy with him, but was relieved when Sumlin met him as he came off the field and put his arm around him.
"It was a mistake that I wish I hadn't made, but he wanted to make sure I was going to learn from it and not do it again," Keenum said. "He's always teaching in every situation that he's in and I think that's a big part of who he is and him being a great coach."
Despite Sumlin's success at Houston, the expectations for Texas A&M in its move from the Big 12 to the Southeastern Conference were low entering this season. The Aggies have proven doubters wrong with a 5-2 record in the SEC, including their upset of then top-ranked Alabama two weeks ago behind freshman quarterback Johnny Manziel.
Those who have known Sumlin longest expected nothing less.
"I'm impressed with everything," Price said. "But it doesn't surprise me."