Dejima joined professional sumo in March 1996 at the age of 22, recruited by Musashigawa stable, home to then ōzeki Musashimaru.

Dejima scored an impressive 11 wins in his top division debut, and was awarded two special prizes, for technique and fighting spirit.

After another 11–4 score in September, in which he won two more prizes and earned his first two kinboshi or gold stars for defeating yokozuna, he made his san'yaku debut at sekiwake in November 1997.

With Musashimaru at yokozuna, Dejima had three of his colleagues in the top two ranks, an advantage as sumo wrestlers never fight members of their own stables except in playoffs.

Dejima held onto his ōzeki rank for two years, with his best result being an 11–4 score in March 2000, but in July 2001 he was forced to pull out of the tournament with only three wins.

Persistent injuries, particularly to his knees and ankles, prevented Dejima from making any sustained attempt to regain ōzeki status.

Near the end of his career he was still capable of producing strong results, as he proved in January 2007 by defeating Yokozuna Asashōryū, the only wrestler to do so in that tournament.

In May 2007 he produced a strong 12–3 record, his second runner-up performance in makuuchi and his highest score in a tournament since his title win, and was awarded his fourth fighting spirit prize.

In the July 2009 tournament, which came exactly ten years after his championship win, Dejima announced his retirement from active competition after suffering nine losses in the first eleven days, rather than face demotion to the second jūryō division.

Sanshō key: F=Fighting spirit; O=Outstanding performance; T=Technique     Also shown: ★=Kinboshi; P=Playoff(s) Divisions: Makuuchi — Jūryō — Makushita — Sandanme — Jonidan — Jonokuchi