Okaizumi is from Kamikawa, Saitama.[1] He began judo with his older brother at the dojo near his house.[2] Okaizumi belonged to Nippon Steel after graduation from Tokai University.
In 1994, he won a gold medal at the Asian Games held in Hiroshima, Japan. In 1995, he also participated in the World Championships held in Chiba but was defeated by Paweł Nastula from Poland (Movie).
As of 2010, he has coached Nippon Steel Hirohata judo club since 2002[3] and All-Japan women's judo team since 2006.[2]
- All-Japan Businessgroup Championships (-95 kg) 1st
- Jigoro Kano Cup (-95kg) 1st
- All-Japan Selected Championships (-95kg) 2nd
- Kodokan Cup (-95kg) 1st
- All-Japan Selected Championships (-95kg) 1st