Instructors

Our fearless leader, Justin Greskiewicz is the head coach and owner of Stay Fly Muay Thai. He lives and breathes Muay Thai. For the last 15+ years, Justin has dedicated his life to the sport. Not only is he one of the most influential people in the sport of Muay Thai in America, Justin is one of the most experienced fighters in the history of American Muay Thai.

A veteran of over 100 fights, Justin has more ring experience than any American fighter. In the ring, he sports his trademark purple hair, earning himself the nickname “The Purple People Eater”. He’s fought on the biggest stages in the sports of Muay Thai and Kickboxing, including Glory Kickboxing, K-1, & Lion Fight. He has fought 14 times on the country’s longest running Muay Thai promotion, Friday Night Fights in NYC.

As a professional, he has won some of the sport’s most prestigious belts to become a WBC International Champion, WBC National Champion, WMC National Champion & WKA Regional Champion.

As an amateur, he was a USKBA World Champion, Siam Dragon Champion & ranked #1 in North America by the WMF.

He has fought for titles including a WBC International Title, WBC National Title, WKA North American Title, WKN International Title, ICO International Title, and USKA World Title in two weight categories.

More than any accolades or ribbons of achievement, Justin has made a name for himself by fighting the absolute best in the sport. Never turning down a challenge, Justin has fought the scariest men on the planet including fighters like Liam Harrison, Kevin Ross, Malaipet, Gabriel Varga, Matt Embree, Kevin Van Nostrand, Asa Ten Pow, Abraham Vidales & Eddie Martinez.

He knows what it means to challenge himself and knows the heartbreak of defeat. His ugly mug has been adorned with over 240 stitches to date.

He is a member of the New Jersey Martial Arts Hall of Fame for his fighting endeavors.

He was one of the premier fighters to establish American Muay Thai in its infancy and was the main event on the first ever full-rules Muay Thai fights in both Pennsylvania and New Jersey.

As a coach, Justin has worked with fighters of all experience levels. He has coached fighters for the UFC, Bellator, K-1, Lion Fight, and promotions all over the world. He has coached first time fighters, professional champions and everything in between.

Justin has been involved heavily as an official in Kickboxing and Muay Thai. He is licensed as an official with the New Jersey and Pennsylvania State Athletic Control Board, the WKA, the ISKA, & holds a position as a USMF official that only a handful of others in the country can claim. He has worked as an inspector for the UFC, a Judge for Lion Fight, and has refereed Glory Kickboxing World Championship title bouts, including one heavyweight title bout. He has refereed multiple WBC title bouts for both National and International Championship titles. He is one of the country’s premier referees and has assisted in the education of referees and judges in efforts to grow an understanding of scoring and to keep fighters safe.

As a teacher, Justin loves imparting his knowledge of the sport. He is eager to share his experience with those around him. He strives to inspire students to find a love for the sport he has dedicated his life to. Whether you’re an absolute first timer, or a professional champion, you will be able to learn a lot from Justin. Justin loves teaching.

Simply put, Justin is one of the most experienced, knowledgeable and passionate Muay Thai experts in the country.