Great Grandmaster Ralph Castro began his martial arts training in 1955 in Hawaii with the legendary William K. S. Chow. In 1958, he began teaching in San Francisco. He later established the first kenpo karate school in Northern California. Since that time Great Grandmaster Castro has taught traditional Shaolin Kenpo to thousands of students, ranging in age from 5 to 77 and from all walks of life. He has produced many top black belts who have become proficient in the art of Shaolin Kenpo. Many students have gone on to teach, producing their own black belts.

Great Grandmaster Castro is proud of all of his students, including his seven children who have each earned high ranking black belts.

In 1981, Great Grandmaster Ralph Castro founded the International Shaolin Kenpo Association (ISKA), having affiliated members and schools worldwide. He is the current president of ISKA.

He is an active member of the American Teachers Association for the Martial Arts (ATAMA), and currently serves on the Board of Directors.

Great Grandmaster Castro's accomplishments have not gone unnoticed. Here is a short list of his many honors:

1982 - Inside Kung-fu, Yearbook
1985 - Official Karate, Cover Story
1987 - Karate Kung-fu Illustrated, Cover Story
1988 - Black Belt, Hall of Fame, Cover Story
1989 - Black Belt, Yearbook, Instructor of Year