An economist, Byambasüren served as the chief of the State Statistical Office and the Institute of Management, although his influence initially waned after the fall of his mentor Jambyn Batmönkh. By 1989 he had risen to the position of deputy head of the Council of Ministers and after the 1990 elections (which were largely democratic) he was chosen as the final Prime Minister of the Mongolian People's Republic. His ministry was noted as reforming but also as something of a technocracy, featuring a number of former communists who had altered their positions to suit the new mood of the country. However he also developed a reputation for diplomacy, visiting Germany, Belgium and France, as well as Moscow and a first visit by a Mongolian leader to China for over thirty years, during the course of his Premiership. He was succeeded in 1992 by Puntsagiin Jasrai. Byambasüren sought to improve Mongolia's external relations and worked particularly closely with Japan who, along with the World Bank, pledged $320 million to the country under his premiership.
He left the Mongolian People's Revolutionary Party in October 1992, criticizing its continuing hegemony in the country and its close links to communist parties elsewhere. He would go on to form his own pro-democracy group the Mongolian Democratic Renaissance Party (Mongolyn Ardqilsan Särgään Mandalyn Nam) in 1994.
In more recent years Byambasüren has been at the forefront of campaigns against moves by teams of archaeologists to dig for the remains of Genghis Khan. Byambasüren attacked both the desecration of sacred ground that the digging caused and the private funding of the initiatives. He has also served as a Professor at the Mongolian Academy of Management and Khan Uul University and President of the Mongolian Development Foundation and participated in the Earth Summit 2002.