Koosed has many years of coaching experience in the Orange County area, including serving as a part-time hitting instructor for the Orange County Flyers in 2008. He also served as an Assistant General Manager for the independent professional baseball team. He joined the Panthers' coaching staff in 2008 serving as primary hitting coach for two seasons. After a year away, Koosed returned to the staff in 2011.

Prior to coming to Chapman, Koosed was an assistant at Foothill High from 2001-07, helping them win six consecutive league championships and one CIF and state championship. In the late 80s, he played and coached in the Royal Dutch Baseball Feberation in Holland. He is also a respected private hitting instructor with his own indoor facility in Anaheim. He played baseball for the Panthers from 1984-85.