John has been a wrestling coach for 26 years. He has spent the last 23 years as the Head Wrestling Coach at South River High School. After three consecutive losing seasons at South River from 2000-2003, the Seahawks have had 19 consecutive winning seasons (no season 2020-21 due to COVID-19). Klessinger’s teams have a 463-147 dual meet record in twenty-two competitive seasons as the head coach. They have won twelve Anne Arundel County dual or tournament titles, five regional titles, and two 4A State Dual Championships. In addition, Klessinger has coached 5 individual state champions and 47 MPSSAA state place winners. He has been the Annapolis Capital Gazette Coach of the Year six times and the Baltimore Sun, Washington Post, Baltimore Banner, and NFHS Maryland Coach of the Year. Klessinger coached for two years at SouthWest Edgecombe High School in Pinetops, N.C. as an assistant in 1998 and head coach in 1999. He was also an assistant coach at Millersville University during the 1997-98 season.

Born and raised in Pennsylvania, Klessinger wrestled collegiately at Wilkes and Millersville Universities from 1992-97. Klessinger was a four-year Division I starter before both schools dropped to Division 3 and 2. He had a career record of 85 – 53, twice placing in the Pennsylvania State Athletic Conference championships and winning the 1997 Division I East Regional tournament. He was a 1997 NCAA Division I National Tournament Qualifier. At Millersville, he was a co-captain and earned the Theodore Rupp Outstanding Wrestler Award in 1997. Wrestling at Warwick High School in Lititz, Pa., Klessinger was a PIAA State Place Winner in 1991 and 1992, placing 5th and 3rd.

In addition to his coaching and wrestling careers, Klessinger has been a high school physical education and special education teacher for 25 years. He has authored two books, "Strong Mind Strong Body" and "A Coach's Manual- Everything You Need To Be A Successful Coach.” Since 2019, Klessinger has written a column for WIN (Wrestling Insider News Magazine) entitled “Writing for Wrestlers” and writes a coaching column for MatBoss, LLC. He instructs personal and group fitness workouts and co-owned at CrossFit gym between 2012-2015.

Klessinger has been married to his wife Kristel for 22 yrs. years and has two children, Ellie, 19, and Mason, 17.