Kōshun Tōjō began playing skeleton in 1998 and has been a member of the Japanese national team since 2002. He contested his first skeleton World Cup race in January 2000 at a race in Lillehammer , which he finished 28th. The Japanese achieved his first top 20 result in that position in December 2001 in Lake Placid . The first major event was the Junior World Championships in 2003, where Tōjō took sixth place. The 2003/04 season was the Japanese’s best. Already in the first races of the season in Calgary and Lake Placid he achieved new best personal results with 15th places, but was able to achieve his best international result in January 2004 with a second place in Lillehammer, where he had to admit defeat only Kristan Bromley . Nevertheless, the Japanese only reached 19th place at the 2004 Skeleton World Championship in Königssee . Until November he regularly took part in World Cup races, but without again achieving a single-digit result. Towards the end of his career he was increasingly used in the Skeleton America's Cup and the Skeleton European Cup . His last race was a European Cup race in Cesana Pariol in December 2007 , where he finished fourth.
Nationally, Tōjō is one of the most successful skeleton pilots. In 2003 and 2004 he won the national titles, ending Kazuhiro Koshi's winning streak . In 2005 and 2006 he won the bronze medals.