Siswono was born in Long Iram in West Kutai Regency on 4 July 1943, during the Japanese occupation of Indonesia.

[3] During his time studying at ITB, Siswono was part of GMNI (Gerakan Mahasiswa Nasional Indonesia, Indonesian National Students' Movement) and Barisan Soekarno - an organization that supported Sukarno, which was censured when Suharto took power.

[1] After graduating, Siswono started a construction firm PT Bangun Cipta Sarana along with his friends from ITB in 1969.

The firm benefited from a construction boom during the Suharto period and was given the contracts to build the graves of Sukarno and Hatta.

[1][2] Following the fall of Suharto, Siswono was the Chairman of the Indonesian Farmers Association, and he represented the "Business Group" in the People's Consultative Assembly between 1999 and 2004.