Etō then assisted Itagaki Taisuke in organizing the Aikoku Kōtō political party, and in composing the Tosa Memorial, a sharp criticism of the government.

In January 1874, frustrated by the government's rejection of his efforts, he returned to his native Saga where both the traditionists and the Seikantō samurai rallied to his support.

Alarmed by growing rumors of unrest, Home Minister Ōkubo Toshimichi dispatched his henchman Iwamura Takatoshi to Saga to restore order.

Etō had expected that similarly disaffected samurai in Satsuma and Tosa would stage insurrections when they received word of his actions, but he had miscalculated badly, and both domains remained calm.

After losing a battle on the border of Saga and Fukuoka on February 22, Etō decided that further resistance would only result in needless deaths, and disbanded his army.

However, Ōkubo was adamant that an example be set, and Etō and Shima were tried by a military tribunal on April 12, and executed the next day along with eleven other leaders of the revolt.

Etō was beheaded at Ōkubo's orders, and his severed head placed on public display – considered a demeaning punishment for someone of samurai class.