Following the surrender of Japan, a group of Indonesian officials approached Hasegawa and requested him to hand over power peacefully to Suwiryo on 7 September 1945.

Though he refused the demand, Hasegawa stopped attending office, resulting in Suwiryo becoming de facto mayor.

[3] During the early parts of the Indonesian National Revolution, Suwiryo continued to lead the city administration of Jakarta despite the military occupation of the Allied forces.

[6] After being arrested for several months, Suwiryo was flown to Yogyakarta - the Republic of Indonesia's new capital - in November 1947 and he became head of demographic affairs of the government, with Daan Jahja becoming the military governor of Jakarta.

This eventually led to the fracturing of PNI's unity in its provincial branches, several members broke off and formed Partindo, and multiple army-backed PNI-affiliated organizations challenged Suwiryo's chairmanship.