During his senior year at Columbia High School, J.J. won the New Jersey high school state title in both the mile and two-mile before attending Villanova University, where he graduated with a degree in communications in 1986. That same year, he returned to Columbia High to serve as the Assistant Track Coach. Setting an incredible example for his athletes, J.J. ran 3:41.5 in the 1,500 meters at the Essex City Twilight Meet and competed at the U.S. Olympic Trials in New Orleans in 1988 before transitioning to collegiate coaching three years later at The University of Florida.

While at U.F., J.J. studied anatomy and physiology in graduate school and also took courses in nutrition and exercise physiology in 1990 at Kean College in Union, N.J., and became certified as a licensed sports massage therapist in 1991 from the Florida School of Massage in Gainesville. J.J. served as the assistant women's track and field coach and head women's cross country coach at Florida from 1992-2001 before heading to The University of Tennessee to become the women's track and field head coach. He served in that role until 2011 before being promoted to Director of Track and Field/Cross Country. Under his direction, the program was led to NCAA women's indoor crowns in 2005 and 2009 and captured three SEC indoor championships and five SEC cross country titles.

Following his tenure at Tennessee, J.J. coached at UCONN, primarily working with distance runners. He guided the Huskies to back-to-back American Athletic Conference women's indoor track and field titles (2015-16), in addition to the school's first AAC women's cross country crown in 2017.

In 2019, J.J. became the 20th head coach/director of the track and field program at Stanford that dates back to 1893. In his first year, J.J. led the Franklin P. Johnson Track & Field program's first conference-region cross country double in 12 years, and the women's best national cross country finish in 7 years.

One of the most decorated middle-distance coaches globally, J.J.'s accolades include being named Coach of the Year 22 times and appointed to the 2008 Olympic team coaching staff. His standout athletes include numerous NCAA champs, National team members, National Champions, World Champions, and Olympians. One of his most notable coaching accomplishments occurred in 2000 when he coached his sisters and wife to a historic sweep of the 2000 Olympic trials.

J.J. lives in California with his wife, Jearl, and son, Jorell.