He was then signed by the Green Bay Packers before the 1992 season. He played for the Packers from 1992–1999. He was an eight-year starter as the Packers returned to dominance, starting 102 of 112 games. He played all three linebacker positions with the Packers and was with the team when they won Super Bowl XXXI.
He was signed by the Seattle Seahawks as an unrestricted free agent before the 2000 season, and started all 16 games. After the 2000 season he retired with 720 tackles, 9 sacks, and 5 interceptions in 128 games.
He was inducted into the National Junior CollegeHall of Fame in 2000 and also the hall of fame at East Carolina University. In 1999, he founded the George Koonce Sr. Foundation to provide underprivileged children with educational, athletic, artistic and social opportunities which assist their development. Koonce's post-career ambitions have been centered around the world of academics. Earning his Master's in Sports Management from East Carolina University and Ph.D. from Marquette University, Koonce has affectionately become known as “The Doctor of Defense.” He is a member of the NFL Player Engagement Advisory Board and has co-authored a book entitled Is There Life After Football? – Surviving the NFL. Currently, he serves as Senior Vice President of the Office of University Relations at Marian University in Fond du Lac, Wisconsin where he provides leadership and strategic direction while being responsible for growing awareness and increasing philanthropic support for the university through community and alumni engagement. Koonce also serves as an on-air personality at Green Bay's CBS affiliate for “Backstage with George Koonce,” and “Locker Room".
East Carolina University
He spent of two years as an Assistant Athletic Director for Development, assisting with fundraising and marketing of the department. He also earned his master's degree in Sport Management in 2006 from ECU.
Green Bay Packers
He served in the Packers front office as the Director of Player Development for the Green Bay Packers for the 2006 season.
Marquette University
He served as the Senior Associate Director of Athletics at Marquette University in Milwaukee, Wisconsin. He was responsible for fundraising, major gifts, community relations, and student welfare. He joined the Golden Eagles in 2007. He also pursued his Ph.D. in Sport Administration while at Marquette.
University of Wisconsin–Milwaukee
He was introduced as the new University of Wisconsin–Milwaukee Director of Athletics on March 17, 2009, and began his duties on April 1. He was placed on administrative leave in April 2010 for undisclosed reasons, and his resignation was announced on June 2, 2010.
Marian University
In 2014, Koonce was hired as the Vice-President of Advancement at Marian University in Fond du Lac, Wisconsin. The university described his job duties as "growing awareness and increasing philanthropic support" within the region.
