Sell was the founder of the United States Chung Do Kwan Association (USCDKA)[2] and the only non-Asian person to be recognized by the World Taekwondo Federation as a 9th Dan Black Belt in the Chung Do Kwan school of Taekwondo, making him the highest ranked non-Asian Tae Kwon Do practitioner in the world.
For much of this time, he was stationed at Osan Air Base in Korea, where he began to study Tae Kwon Do.
In 1974, he renamed his organization the "United States Chung Do Kwan Association" and relocated it to Lakeland, Florida.
Sell, a 9th Dan Black Belt[6] and the only recognized female American Tae Kwon Do Grandmaster.
It currently contains nearly 250,000 members and over 4,000 black belts,[citation needed] and is considered one of the oldest Taekwondo organizations in the United States.