In the 2000 24 Hours of Le Mans Kageyama's Team Dragon squad finished sixth overall in their Panoz LMP-1 Roadster-S. Kageyama also rebounded in JGTC and finished second in points in his Skyline GT-R. In 2001 Kageyama fell to seventh in JGTC and returned to Formula Nippon, finishing ninth in points. 2002 was a very disappointing JGTC season with Kageyama only finishing 28th in points. In 2003 however, he rebounded to fifth in points in his NISMO Skyline GT-R. In 2004 he stayed with the NISMO team as they switched cars to the new Nissan Fairlady Z. Kageyama finished ninth in points. In 2005 he dropped down to the GT300 class still driving a Fairlady Z, but switched teams to Endless Sports. He finished sixth in GT300. He improved to fourth in 2006 in the same car, team, and class. The same combination finished fifth in points in 2007.