Derek Keizer graduated Dordt College in 2007 and played four seasons for the basketball team. He finished the program as the career leader in assists with 498 and second all-time in steals with 192. He coached the Dordt junior varsity team in 2007-08 before taking a teaching position at Crown Point Christian School in St. John, Indiana, for the 2008-09 school year and served as an assistant at Dordt in 2009-10 and 2011-12. He also taught and coached at San Jose Christian (California) in 2010-11.
During Keizer's time on the bench the Defenders have won on GPAC regular season title and a GPAC post-season tournament champioship. Dordt has earned two NAIA Division II National Tournament berths in his time with the Defenders.