In his first 28 seasons as head coach of Moravian, John Byrne has guided the Greyhounds to a 894-252 record, three NCAA Division III World Series appearances, 18 NCAA Division III playoff berths, 24 conference playoff appearances and 19 conference championships. Byrne earned his 800th career victory on April 5, 2018 with a 3-2 win over DeSales University, and he reached the 700-win plateau in the first game of a doubleheader versus the College of Staten Island on April 25, 2015.

In 2021, Moravian reached the postseason for the 26th  season and finished the year with a 31-3 record, setting marks for best winning percentage (91.2) and fewest losses while the 2018 team won the Landmark Conference Championship, the NCAA Division III Ewing N.J. Regional title and plaed in an NCAA Division III Super Regional at Rowan University. In 2009, Byrne became the first coach in school history in any sport to win 500 games, and in June 2011, he was inducted into the Lehigh Valley Softball Hall of Fame at Pates Park in Allentown.

Byrne and his staff were named the Landmark Conference Coaching Staff of the Year in 2008, 2011, 2016,  2017, 2018, 2019 and 2021, and Byrne and his staff were named the National Fastpitch Coaches Association Regional Coaching Staff of the Year in 2003, 2004, 2007 and 2010. Byrne was the Commonwealth Conference Coach of the Year four times, and he was the ECAC Division III South Coach of the Year in 2016.

Byrne, a 1982 graduate of Moravian, served as Athletic Recruiting Coordinator from 1985 to 1998. He also served as Associate Athletics Director for the Greyhounds. A four-year starter on the baseball team, Byrne was an assistant baseball coach from 1983 to 1992, head volleyball coach in 1988 and assistant football coach from 1989 to 1997. Byrne served as associate head coach of the Philadephia Force in the National Pro Fastpitch League in 2007 and has worked as an associate scout for the Cincinnati Reds. He resides in Bethlehem and has daughters, Rachel and Jamie.