Coach Greynolds graduated from Tanner High School in West Virginia in 1949 and from Anderson Broaddus College in 1953. He received his Masters degree from West Virginia University in 1960. Jack never had a losing season in 29 years in high school coaching and during that time had four undefeated regular seasons. He had the third longest winning streak in Ohio basketball history - 51 games. His coaching career included two years at Pratt Junior High in West Virginia (1955-1957), 12 years at Revere High School (1957-1969), and 17 years at Barberton High School (1969-1987). Over all his high school teams won 549 and lost 121 for 82.9%. They won 16 sectional, six district, three regional and one State Championship. Barberton won the State Championship in 1976 and was runner-up in 1977 and 1982. Jack was Summit County Coach of the Year an unprecedented five times - 1971, 1973, 1975, 1976 and 1984. In 1977 Jack received the following honors: Coached Ohio All-Stars vs Russian Nationals, UPI and AP Coach of the Year, National (Prep Sport) Coach of the Year, Akron Dapper Dan Man of the Year, Summit County Hall of Fame and Barberton Sports Hall of Fame. In  1975 he coached the AAA North squad in the North-South All-Star game and was UPI Coach of the Year. In 1988 he was the first inductee into the Greater Akron Area Coaches Hall of Fame.

While at Revere High School he won or co-champed the Suburban League eight times in 11 years. Jack was also head baseball coach for eight years and while at Pratt Junior High coached football and baseball as well as basketball.

As a high school and college player Jack was outstanding. He was All-State in High School and All-Time All-Conference player in the WVIAC.

Jack had to give up coaching in 1987 when he suffered a stroke. He will never be able to speak again. Jack and his wife, Mary have one son Jack Jr. who played for him at Barberton and in now head basketball coach at Rootstown.