He participated in drawing up a draft of the proclamation of the independence of Korea in 1918 while he was studying in Japan, and after 1919, left for Shanghai to join the Provisional Government.

He also organized the society of policies on current affairs with Kim Ku and Yeo Unhyeong, contributing to establish the theories on diplomacy of the provisional government.

In the midst of dividing political alliances, Jo So-ang remained loyal to the Provisional Government of the Republic of Korea and was elected as their secretary and diplomatic correspondent.

In March 1921, after attending the Communist Party Congress in Moscow, Russia, he returned to Beijing with critical views on communism.

Not only did his theories guide the Korean Independence Party during the occupation, but also served as the main foundations of legislation for the country post-liberation.