Pushyamitra Shunga was the foremost and the most famous king, who founded the Shunga Dynasty. During his reign the Shunga Empire reached its culmination in the fields of art, architecture, literature etc. After a reign of 36 years, Pushyamitra died in 152 B.C. and was succeeded by his son Agnimitra. The Shunga dynasty during the reign of the later Shungas, however lost the former magnificience it had earned during the reign of Pushyamitra Shunga. Hence it has been a subject of keen debate, whether the later Shungas ruled in pale glory of fading imperial spark. According to Dr. Roychowdhury, the successors of Pushyamitra ruled in undiminished glory upto the third generation of the Shunga lineage. Prof. Jagannath supported the theory approached by Roychowdhury and puts forward that, right from the reign of Vasumitra, grandson of Agnimitra, forces of disintegration and disruption was set forth in the Empire. But Dr. S. Chattopadhya though refuted the views and holds that there was no Empire after the Shungas. However most of the historians believed that during the third generation of the Shungas, the strong foundation of the Shunga Dynasty was destabilised.

During the later Shunga rule, the Shunga Empire was disintegrated owing to the strife between petty political parties. After the death of Pushyamitra, Northern India was divided into minor political units. All these kingdoms were feudatories of the Shungas. But the local chiefs of these feudatories declared their independence after the death of Pushyamitra Shunga. The Ayodhya inscription of Dhanadeva engraved that the later Shungas could not maintain the Empire in an appropriate manner. Hence the local governors revolted and the Shunga king at the centre could not subdue that. Moreover historians have also put forward that the later Shungas were detached from the city of Pataliputra and confined to the city of Vidisha. Furthermore historians have also stated that after the death of Pushyamitra, the later Shungas were reduced to the position of petty local rulers of Vidisha.

Pushyamitra had a competent heir Agnimitra, who succeeded him. Though no detailed facts about the reign of Agnimitra is available, yet, historians have opined that he was the governor of Vidisha during the reign of his father. Agnimitra conquered Vidarbha and annexed it to the Shunga Empire. He ruled for a period of 8 years and was succeeded by Vasujyestha. About Vasujyestha, historians have opined that he ruled the major section of Northern India and was credited to have completed the Ashwamedha Yajna of his grandfather successfully after beating the Indo-Greeks at the banks of the Indus. Vasumitra rescued the Shunga Empire again from the Yavana invasion. But he lost his martial spirit after he ascended the throne and lived a life of dissipation. In the midst of such dramatic performances, Mitradeva or Muladeva killed Vasumitra. Historians have opined that the assassin might have been a scion of the Kanva family, which later overthrew the Shungas. The Puranas mentioned three kings after Vasumitra, namely Andhraka, Pulindaka and Ghosa, who ruled in fading glory.

The next Shunga king who owes some importance was Bhagavata, who ruled for a period of 32 years. During his reign hostility of the Shungas with the Yavanas had turned into a peaceful and friendly relationship. Devabhuti succeeded Bhagavata in 82 B.C. According to Bana, Devabhuti was a licentious man. His minister Basudeva had designed a plot, by which a slave girl in the guise of a queen had murdered Devabhuti. Devabhuti was the final king of the Shunga lineage and with his death in 72 B.C., the Shunga Empire was completely demolished. After the fall of the imperial Shunga line, the surviving members of the family continued to exist as the local chiefs under the Kanvas, who were at that time in the helm of administration.