Stephen Randall Thompson, known to fans as “Wonderboy,” is an American mixed martial artist and former professional kickboxer who has spent more than a decade as one of the UFC’s most consistent welterweight contenders. He was born on February 11, 1983, in Simpsonville, South Carolina, and began training in martial arts at age three under his father, Ray Thompson, a former professional kickboxer who founded the family’s karate school, a background documented on his Wikipedia biography.

Thompson has two sisters and two brothers, and the family remains closely tied to the sport. One of his sisters is married to Brazilian jiu-jitsu instructor Carlos Machado, who has coached Thompson on the ground, while his brother Tony is married to the sister of former UFC middleweight champion Chris Weidman. Thompson holds a 7th degree black belt in American Tetsushin-ryu Kempo, a 1st degree black belt in jujutsu, a black belt in American kickboxing, and a brown belt in Brazilian jiu-jitsu, credentials laid out in the same Wikipedia profile of his career.

Before he ever competed in mixed martial arts, Thompson built one of the most dominant amateur kickboxing resumes in the sport. He compiled a 37-0 amateur record with 18 knockouts and collected 16 national and world titles, including the 2000 and 2001-2002 IKF national tournament championships and the 2005 WAKO World Championship at cruiserweight, a run detailed on Wikipedia’s account of his amateur career.

Thompson turned professional as a kickboxer on May 15, 2004, stopping Kadir Kadri in the fifth round, and went on to a 20-0-1 professional kickboxing record with 10 knockouts. He fought undefeated for the World Combat League in 2006, and a January 2007 bout against Raymond Daniels that was initially ruled a TKO loss due to a knee injury was later overturned to a no contest. That injury pushed him toward mixed martial arts, where the UFC’s own retrospective on his path to the octagon describes his transition as a natural extension of an already elite striking base.

Thompson made his UFC debut on February 4, 2012, at UFC 143, knocking out Dan Stittgen in the first round with a head kick to earn a Knockout of the Night bonus. He suffered his first professional loss that April at UFC 145, a unanimous decision to Matt Brown, an early setback that the fighter has described as a turning point that pushed him to sharpen his grappling defense alongside his striking.

The following years produced a run of highlight-reel finishes that established him as a top contender. He stopped future middleweight champion Robert Whittaker in February 2014, knocked out Jake Ellenberger with a spinning wheel kick in July 2015, and finished former welterweight champion Johny Hendricks in February 2016, each performance earning a Performance of the Night bonus. A June 2016 unanimous decision over Rory MacDonald completed the streak that put him in line for a UFC title shot, a stretch of his career profiled in the UFC’s feature on his rise to title contention.

Thompson’s biggest career moments came in back-to-back fights against then-champion Tyron Woodley for the UFC Welterweight Championship. At UFC 205 in November 2016, the two fought to a majority draw, a result that caused on-air confusion when it was briefly announced as a decision for Woodley before being corrected, as reported by CBS Sports’s coverage of the event. Both fighters earned Fight of the Night bonuses.

The rematch at UFC 209 in March 2017 went the other way on the scorecards, a majority decision for Woodley that split media opinion almost evenly. Thompson has never captured UFC gold despite the two title opportunities. Later career highlights include a dominant decision over Jorge Masvidal at UFC 217 in November 2017, a Fight of the Night win over Vicente Luque at UFC 244 in 2019, and a Fight of the Night stoppage of Kevin Holland in December 2022. His professional MMA record stands at 17 wins, 9 losses and 1 draw, per the UFC’s official athlete profile.

Thompson is widely regarded as one of the most technically distinctive strikers in UFC history, built on the wide, low-handed karate stance and rapid footwork he developed from childhood. That profile has carried him well beyond the cage. He signed with modeling agency IMG Models in 2017, made his acting debut as Sensei Morozov in two episodes of Netflix’s “Cobra Kai” in its 2022 fifth season, and appears in the 2025 documentary film “Paperweight,” milestones referenced in coverage such as TOWN Carolina’s profile of his career and life in South Carolina.

He is also frequently cited by MMA media as one of the sport’s most respectful competitors and among its most decorated strikers, a reputation built on his sportsmanlike conduct in both wins and losses, including in his two closely contested title fights against Woodley, a standing echoed in Dynamic Striking’s profile of his career.

Thompson’s commercial profile grew substantially after he signed with IMG Models in 2017, a deal that led to a national advertising campaign for menswear brand Van Heusen and an appearance in a GQ web series in which he broke down martial arts choreography in film, both noted in TOWN Carolina’s account of his modeling work. Like most active UFC fighters, he has also carried standard fight-week sponsorships and apparel arrangements tied to his bouts, though the promotion does not disclose the value of those individual deals.

Exact contract terms and durations for his modeling and endorsement work have not been made public, and no independent outlet reviewed for this profile has published a specific dollar figure for that income stream.

Thompson’s primary venture outside competition is Upstate Karate, the family martial arts academy in Simpsonville, South Carolina, founded by his father Ray Thompson in 1983. The school has grown into a 20,000 square foot facility with a full-size kickboxing ring, a 24 foot cage and 6,000 square feet of mat space, according to TOWN Carolina’s reporting on the business. Thompson serves as head coach of the children’s program, teaching roughly 600 students between the ages of three and thirteen, and has described the teaching role as “my first love.”

Unlike some UFC contemporaries, Thompson has not publicly disclosed any outside company ownership, franchise stake or equity investment beyond his role at the family academy. His business identity remains closely tied to the gym that shaped his own career.

Thompson has not publicly disclosed personal real estate holdings, vehicles or other major assets, and no primary outlet reviewed for this profile documents a specific property purchase or address. What is confirmed is that he lives and trains in the Simpsonville, South Carolina area, where his family operates the 20,000 square foot Upstate Karate facility described in TOWN Carolina’s reporting, itself the family’s most significant documented physical asset.

Coverage of Thompson consistently notes that he keeps a low public profile around money, and figures for personal property circulating on some secondary net worth sites are unconfirmed estimates rather than documented purchases, so they are not treated as fact in this profile.