A member of the Indonesian Democratic Party of Struggle, he previously served as speaker of the People's Consultative Assembly, from 2013 until 2014, following the death of Taufiq Kiemas.

Joining Sukarno's daughter, Megawati Sukarnoputri's Indonesian Democratic Party of Struggle (PDI-P), and was elected as a member of the People's Representative Council from the West Java VII electoral district.

He firmly asked the Indonesian Armed Forces not to hesitate to sink a neighboring ship that was proven to have passed through and entered the country's territory.

[5] In 2013, when Speaker of the People's Consultative Assembly Taufiq Kiemas died on 8 July 2013, Sidarto was chosen to replace Taufq.

[8][5] In 2015, following the election and inauguration of Joko Widodo as the new president, replacing Susilo Bambang Yudhoyono, he was officially sworn in as a member of the Indonesian Presidential Advisory Board, a non-structural government agency, on 19 January 2015.