He began training in the Iwama Dojo at the age of 12 as a direct student of the founder of aikido, Morihei Ueshiba in June 1949.

Isoyama was made the acting head of the Iwama dojo on behalf of Ueshiba Moriteru following the passing of Morihiro Saito.

[4] Along with Hiroshi Tada, Isoyama formed a committee for the construction of a large statue of the founder of aikido in the precincts of the Aiki Shrine, which was unveiled on 8 November 2009.

Funding was mainly obtained via a call for donations[1] and surplus material from this monument was used to make a bust of the founder which was unveiled at the newly rebuilt Iwama Station on 24 July 2012.

[2] Before retiring, Isoyama Shihan also served for many years as a Senior Council Member for the International Aikido Federation (appointed by IAF president) and he is notably responsible for the introduction of demonstrations at the end of each congress.