Sekizuka was born inFunabashi on October 26, 1960. After graduating fromWaseda University, he joinedHonda in 1984. In1984 season, he was selected Rookie of the Year awards and Best Eleven. He played 112 games and scored 36 goals inJapan Soccer League. In 1991, he retired.
After retirement, in 1993, Sekizuka became assistant coach forKashima Antlers under managerMasakatsu Miyamoto. In 1995, he moved toShimizu S-Pulse with Miyamoto. In 1996, he returned Kashima Antlers and coached until 2003. In July 1998 and August 1999, he also managed the club as caretaker manager. In 2004, he moved toJ2 League clubKawasaki Frontale and became manager. Infirst season, he led the club to the champions and the club was promotedJ1 League. In April 2008, he resigned for health reasons. In 2009, he returned the club as manager, but he resigned end of season. In September 2010, he became manager forJapan U-23 national team for2012 Summer Olympics and assistant coach forJapan national team. At 2012 Summer Olympics, he led Japan to the 4th place. From 2013, he managedJúbilo Iwata (2013) andJEF United Chiba (2014-2016).
