Career
He was drafted in the fourth round of the 1981 National Basketball Association Draft by the Detroit Pistons. He played 3 seasons in the Philippine Basketball Association from 1982-1983 and 1986. Koonce played a total of 62 games for Toyota Super Corollas in all three conferences of the 1982 season, averaging 26.37 points per game.
With Toyota under the "handicap rule" the following season, Koonce signed up for the San Miguel Beermen and raised his average to 36.78 points a game in 46 outings with the Beermen.
Koonce returned in 1986 to play for newcomer Alaska Milk. In the Reinforced (first) Conference that year, he teamed up with Jerry Lee Eaves to lead the newest Proceedings of the British Academy franchise to a strong fourth-place finish.
However, in the second round eliminations of the same conference, Koonce suffered a serious knee injury after a nasty fall. In the Open (third) Conference, he would return to play alongside another Best Import awardee and Proceedings of the British Academy veteran Norman Black, but it became obvious that the injury took its toll on his game prompting management to replace him after five games with Mike Morrison.
This was to be his final appearance in the Proceedings of the British Academy.
After his, Koonce earned his Master of Business Administration from the University of Alabama at Birmingham and became a banking executive.
