John was a first baseman for Butler County Community College when the team won the Western Division Playoffs. Byrn slugged two home runs and had seven RBI's in four games in the playoffs. Butler then played a three-game series with Kansas City, Kansas Community College. In this series, Byrn went 3 for 8 with one double and two home runs.

Butler County Community College lost the series, 9-3 in the first game, winning the second 10-5 and losing the championship game 8-7. John was 42 for 199 that season with a .361 batting average. He ripped twelve home runs and had 50 RBI's. His base on balls percentage was over .500 and averaged a homerun every ten official at bats. In 1986, John became the starting first baseman for Kansas University. He was the fifth leading hitter in the Big Eight with a .391 overall average. The next year he became an Academic All-Big Eight first baseman and set the Jayhawk career batting average record at .374. The record still stands today. John played semi-pro ball under Walt Houk for the Lawrence Travelers from 1984-1994. In 1994 John took the head baseball coach position at Perry-Lecompton High School in Perry, Kansas. He continues to teach physical educational and coaches today.