[1] Prabhu Dayal Singh belonged to Gopalganj district of Bihar and he represented Mirganj Assembly constituency, which is known as Hathua Assembly constituency from 2010 onwards.
[1] He first won the 1985 Bihar Assembly election from this constituency on the symbol of Indian National Congress.
However, he was able to retain this seat again in 2000 Bihar Assembly election, when he won for the third term.
He was fielded from Gopalganj Lok Sabha constituency before it was reserved for the Schedule Castes.
In 2020 Bihar Assembly election, he defeated Ramsewak Singh Kushwaha of Janata Dal (United), a four-time MLA from Mirganj-Hathua Assembly constituency, to become a legislator for the first time.