He is best known for his role as Eiji Kikumaru in The Prince of Tennis musical series, Tenimyu, and in the live film adaptation.
He was also a part of the Watanabe net drama "Hice Cool" (2005) and "DD-BOYS", appearing alongside fellow D-Boys members.
But, by the end of January 2007, it was announced to fan club members that while Adachi was still being represented by Watanabe Pro, both he and Yuma Minakawa had officially withdrawn from the group.
Since his graduation, the role of Kikumaru has been played by D-BOYS member Kōji Seto, Kyousuke Hamao, Shouta Takazaki, Yuta Koseki and currently by Kuroba Mario.
The Prince of Tennis was released on May 13, 2006 and opened on the tenth spot in the Japanese Box Office and marked Adachi's first appearance in the film industry.