Sheahon began practicing aikido in 1972 in Tokyo at the aikido world headquarters (Hombu Dojo) where he trained for 12 years. He began teaching aikido in 1978 when he founded the Nonotuck Aikikai in Northampton, Mass. He later served six years as assistant instructor to Seijuro Masuda Shihan (master teacher), eighth-degree black belt (hachidan), at the International Aikido Club in Tokyo. He founded Aikido-Wichita in Wichita, Kan., in 1989.