John Schaefer lettered in football, wrestling and track while pursuing his bachelor's degree in physical education at Springfield College.

After pursuing his master's degree in physical education, John had a brief coaching stint in New Jersey before arriving in the Bellmore Merrick school district in 1965. It was there that he learned coaching techniques and philosphy from legendary coaches Sprig Gardner, a Distinguished Member of the National Wrestling Hall of Fame and Ken Hunte, a Lifetime Service to Wrestling award recipient.

Schaefer was the head coach and coached two undefeated teams at Grand Avenue Junior High School. In his first season at head coach at Bellmore-Kennedy High School in 1968-69, Schaefer won his first Nassau County team championship and was named Coach of the Year. During his tenure from 1969 to 1979, he led his teams to four Nassau County championships and had three undefeated seasons.

John, who returned in 1995, had a career dual meet record of 44-86-9 while winning 20 league, conference, division, and qualifying championships and eight holiday championships. He coached 87 county place-winners and 13 state place-winners, including five finalists. Two of his most successful wrestlers were Steven Cavayero, a two-time NCAA champion for SUNY Binghamton University, and two-time New York State champion Steve Hunte, who was a two-time Big Ten Conference champion and two-time NCAA qualifier for the University of Iowa.