As a politician, he was the member of the Regional People's Representative Council of Minahasa from 1947 until 1952, and from 1952 until 1954, he became its chairman.

[1] His theological career begin in 1948 when he was chosen as the vice head of the Minahasa Evangelical Christian Church from 1948 until 1950.

Prior to his election as the chairman of the party, he had already become the member of the Minahasa Regional People's Representative Council from 1937 until 1952, and from 1952 until 1954 he became the speaker.

In the 1955 Indonesian legislative election, Sondakh was chosen as the member of the People's Representative Council of the North and Central Sulawesi electoral district.

Sondakh was chosen as the general secretary of the Indonesian Christian Party at its 7th congress from 4–5 February 1961 in Jakarta.