John Danaher (born 1967 in Washington, D.C., United States) is a New Zealand Brazilian jiu-jitsu and mixed martial arts instructor. He holds a 4th degree black belt in Brazilian jiu-jitsu under Renzo Gracie, and is an instructor at the Renzo Gracie Academy in Manhattan. Danaher grew up in New Zealand and arrived in the United States in 1991 to study at Columbia University's philosophy PhD program. After arriving in New York, Danaher was introduced to Brazilian jiu-jitsu by a friend at the university, and began taking classes at the Renzo Gracie Academy in Manhattan. He continued training at the academy and began to teach classes as well while Gracie was traveling for competition. Since receiving his black belt in April 2002, he has been an instructor for several notable jiu-jitsu and mixed