Subsequently, an election to determine leaders was held, and Ezo Republic (headquarters in Goryokaku) was established; Toshizo, as one of the leaders, became vice-minister of the Army and concurrently served as Torishimari of Hakodate city and chief of the Court of the Army and the Navy.
その後、幹部を決定する選挙が行われ、榎本を総裁とする蝦夷共和国（五稜郭が本陣）が成立、歳三は幹部として陸軍奉行並となり、箱館市中取締や陸海軍裁判局頭取も兼ねた。