Cornelius's first exposure to martial arts training began at a young age, under his step-father, martial arts teacher Tom Callos, who was BJ Penn's first Brazilian jiu-jitsu instructor. At the age of 14, he began casual grappling training with friends. Shortly thereafter, he began receiving formal Brazilian Jiu-Jitsu instruction under Cassio Werneck, then training for three years under BJ Penn, before ultimately joining with Team Lloyd Irvin. Despite his high-level victories as a purple belt and above, Keenan claims to have had a poor competitive showing early in his career, prior to his joining Team Lloyd Irvin, a move which Keenan held responsible for his later success.
Career
On February 28, 2012 Keenan won the Abu Dhabi World Pro Trials Montreal Purple belt +74 kg absolute division. In April 2012 Keenan competed in the World Pro Jiu-Jitsu Cup, winning his division and earning a bronze in the absolute division. On June 26, 2012 Keenan was promoted to brown belt under Lloyd Irvin. On February 27, 2013 Keenan announced his split from Team Lloyd Irvin. A few days later, it was officially announced that he would be joining Atos Jiu-Jitsu. After his transition to Atos, Keenan continued his run as arguably the most accomplished brown belt in the history of the sport, winning nearly every major tournament at his weight and open class with the only exception being the 2013 IBJJFBrown Belt Absolute Division where he placed second. On September 14, 2013 Keenan was promoted to black belt under André Galvão. On December 8, 2013 Keenan won the medium-heavy/heavyweight division of the 2nd IBJJF Pro League for the prize of $5,000 by defeating Diego Gamoral and Jackson Souza. On March 29, 2014, Keenan was scheduled to face Vinny Magalhaes in Metamoris III. However, Vinny was forced to withdraw before the match, being hospitalized with a MRSA infection. He was replaced by Rickson-trained black belt Kevin Casey. The match ended as a win for Keenan, using 50/50 guard and getting a submission with an inside heel hook. In April 2014 Keenan competed in the 2014 Abu Dhabi BJJ World Pro Championship, winning bronze in the black belt adult 94 kg division. On August 9, 2014, Keenan competed against Vinny Magalhaes at Metamoris IV. The match ended in a draw. On November 22, 2014, Keenan competed against Yuri Simoes at Metamoris V. The match ended in a draw. On January 10, 2015, Keenan competed against Dean Lister at Polaris Pro Grappling. He won the match with a reverse triangle choke from back control.
Legion Academy
After a falling out with his long time gym ATOS, Keenan decided to open his own gym and fight team. On August 6, 2019 he announced he would open Legion Academy in San Diego CA. Since launching the Legion AJJ academy, Keenan Cornelius has attracted some of ATOS' top athletes to his team including Andris Brunovskis and Darin Conner DeAngelis.
Technique Development
Keenan is known in the Brazilian Jiu-Jitsu community for his creation and successful use of a unique gi guard system. Nicknamed the Worm Guard by André Galvão, Keenan ties his leg to his opponents hip and opposite leg with one hand and his opponent's loose lapel, locking them into place while leaving Keenan two free limbs to attack on one side. He and others have continued to iterate and invent techniques exploiting the lapels of the Gi jacket, a trend that is credited to Keenan's initial success with Worm Guard.
Media
In 2013, Cornelius published a 5-part DVD set teaching concepts of his competition style. In 2016 Keenan Online, a membership site, began offering his curriculum.
