Prof. Willy Cahill is one of the Founders, past President, and Technical Director of Jujitsu America. He serves for the US Judo Association's Jujitsu program on the Jujitsu Executive Committee and Standards Board. He holds 10th Dan in Jujitsu and 8th Dan in Judo. Besides running his own dojo, Cahill's Judo Academy, in San Bruno, CA, which celebrates its 60th anniversary in 2008, he coached the U.S. Olympic Judo Teams in 1984 and 1988, the World Team five times, the Pan American Team twice and the Goodwill Games twice. Since 1963, Cahill's Judo Academy has produced over 1000 national and international medal winners, and four Olympic and Paralympic coaches. Coach Cahill was the judo coach at both San Francisco State University and Stanford University. He was head coach of the Paralympic Judo Team that traveled to Sydney, Australia in November, 2000 and brought back the first Gold Medals ever won by the U.S. in Paralympic or Olympic judo competition. The team was ranked #1 in the world in 2000.

In 1997, Prof. Cahill started The World of Martial Arts Supplies, a company dealing with martial arts supplies as well as nutritional products, with the majority of his business online at his website. He has developed a set of 3 instructional videos that demonstrate Judo Training, as well as a 6-volume video set demonstrating the arts of Kodenkan Jujitsu. He has also designed a line of judo and jujitsu uniforms for Tiger Claw.

Prof. Cahill is honored to work closely with his student Eric Renner to present Sport Jujitsu Tournaments and events several times a year, culminating with the annual Jujitsu America Sport Jujitsu US National Championship Tournament. These tournaments and events are presented in longtime partnership with Tiger Claw.

Prof. Cahill has received numerous awards, including being named to Black Belt Magazine's Black Belt Hall of Fame as Judo Coach of the Year, JA's Instructor of the Year in 1979, inducted in 1981 to JA's Black Belt Hall of Fame, was the 1997 recipient of JA's Wally Jay Award, and recognized in 2006 with JA's Patriarch Award.