Hargrave received multiple martial arts system training from instructors located throughout the United States, and currently holds black belts in seven styles. In 1993 he received the Instructor of the Year award for his teaching in the art of Jeet Kune Do, the style founded by Bruce Lee, and was also inducted into the Martial Arts Hall of Fame. In 1995 Hargrave was the youngest person to be promoted Professor of martial arts, and he received the Instructor of the Year award for his teaching in Karate. In 1996 he received the award for Best Martial Arts School in the United States, and was recognized by U.S. Congress, the United States Senate, and the Governor of Oklahoma for this achievement.
Hargrave holds instructor / black belt level rankings in Kempo Karate, Kung Fu, Goshin Jutsu, Jeet Kune Do, Aiki Jitsu, Tae Kwon Do, and Escrima, as well as the author of three martial arts books, two on Japanese Kempo Karate and The Original Jeet Kune Do Training Manual which contain Bruce Lee's techniques from the Oakland and Los Angeles schools.. Hargrave is the founder of the style known as American Combat kempo which he introduced in 1992, and in 2000 was presented the International Founders Award by Dr. E.A. Moore (President of the World Martial Arts hall of Fame) for the defense system. This system is used by the United States Marines as the basis for their training since 2000. Hargrave has been inducted into numerous martial arts hall of fame's and was Grandmaster of the Year in the United States Martial Arts Hall of Fame.