A member of the ruling Ni-Ki-San-Suke Manchukuo clique (see zaibatsu), Hoshino graduated from the law school of Tokyo Imperial University, and on graduation was employed by the Ministry of Finance.
Anggota penguasa Ni-Ki-San-Suke Manchukuo clique (lihat zaibatsu), Hoshino lulus dari sekolah hukum Universitas Kekaisaran Tokyo, dan pada kelulusannya dipekerjakan oleh Departemen Keuangan.