The 31-year-old South Carolina native went 57-0 as a kickboxer, winning numerous titles. As a mixed martial artist, he has won nine of 10 fights.
Thompson looks for MMA win No. 10 as he takes on Montreal welterweight Patrick (The Predator) Cote at UFC 178 in Las Vegas on Saturday night.
"You'll see some fireworks," Thompson predicted.
A loss via decision to Matt (The Immortal) Brown at UFC 145 in April 2012 is the lone blemish on his record.
Thompson (9-1) knocked out Dan Stittgen in his UFC debut 2 1/2 months earlier at UFC 143. Two days after the win, he got a call offering the Brown fight. He said yes, hiring a new strength and conditioning coach.
Perhaps as a result, he bulked up to 209 pounds. That was heavy for Thomspon, who suffered through the weight cut to 170 pounds.
"Matt Brown did exactly what he said he was going to do," Thompson said with a laugh. "He kicked my butt. But it was a war. I would love to do it again. Matt Brown's a good dude and a great fighter. He's made it up to the top and man, he's a monster."
A knee injury sidelined Thompson for the next year. He has not lost since, beating Nah-Shon Burrell, Canadian Chris Clements (in Toronto), and Robert Whittaker.
The knee problems started eight years ago during a fight against Raymond Daniels in Chuck Norris' World Combat League. He tore every ligament in his left leg, had 40 per cent of his meniscus removed and underwent three surgeries.
Doctors told him he would never fight again.
"It was rough," he said. "Not just physically but mentally."
In all he sat out three years, during which time he started leaning towards switching to MMA. His striking skills had already won him invitations to train with some of the best.
"At the time I was training with guys like Georges St-Pierre, Rashad Evans, Nate Marquardt. During this injury I had some time to kind of think about where I wanted to go with my fight career."
Years later his knee rehab is still a daily affair but he says it feels good. And it hasn't seemed to affect his kicking arsenal or the corkscrew-somersault move that he celebrates wins with, although he says he had more celebratory moves before the injury.
In the days leading up to this bout, Thompson managed to combine his training camp with teaching classes at the family gym, Upstate Karate in Simpsonville, S.C.
The gym was opened 31 years ago by Ray Thompson, Stephen's father. Stephen and his two brothers and two sisters all started their martial arts journey at the age of three.
Now they run the business with almost 650 students. And Stephen fights.
Stephen began with kempo karate. At 12, he put his jiu-jitsu and wrestling on hold to focus on kickboxing with his first amateur bout at 15.
Today he is a fifth-degree black belt in kempo karate, a discipline that is a key part of his mixed martial arts attack.
Thompson changes stances, darts in and out, and has a dizzying array of kicks. He is not easy to prepare for — or face.
Thompson has ties to Montreal, having helped former UFC champion St-Pierre prepare for several fights.
"I love Montreal," Thompson said. "I love the people, I love the history."
Thompson sparred briefly with Cote (21-8) in 2008 before switching his focus to MMA.
"It's an honour to fight somebody like him," said Thompson, noting Cote's extensive resume. "He's gone three rounds with (former middleweight champion) Anderson Silva. He's fought Tito Ortiz. He's fought some of the greats in the UFC."
Like Cote, Thompson has added to his arsenal. While known as strikers, both men have taken down opponents in recent bouts.
But Thompson knows his bread and butter.
"Striking is what I do. Everybody wants to see somebody get knocked out," he said. "I'm sorry but it's the fight game and that's what they want to see."
Thompson has trained with Chris Weidman several times and the UFC middleweight champion returned the favour for the Cote camp.
"That's just the kind of guy he is," said Thompson.
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