B. P. Mandal was a Member of Parliament in the Lok Sabha for the state of Bihar from 1967 to 1970 and 1977 to 1979. He was also the Chief Minister of Bihar for forty-eight days in 1968, a period of intense political instability (his predecessor was Chief Minister for only three days). In December 1978, Prime Minister Morarji Desai appointed a five member civil rights commission under the chairmanship of Mandal. The commission's report was completed in 1980 and recommended that a significant proportion of all government and educational places be reserved for applicants from the Other Backward Classes. The commission's report was tabled indefinitely by Prime Minister Indira Gandhi. A decade later, Prime Minister V. P. Singh implemented the recommendations of the Mandal Report.
B. P. Mandal was born in a Yadav family in Banaras, India. He was raised in the village of Murho, in the Madhepura District (formerly Saharsa District) of northern Bihar. Mandal received his early education in Madhepura and he attended Raj High School in Darbhanga. He matriculated at Patna College in the 1930s and worked as an Honorary Magistrate from 1945 to 1951. His political career began with the Indian National Congress but he joined the Janata Party after the Emergency Period. Later in his political career, Mandal gravitated toward socialist political ideas and he eventually joined the Samyukta Socialist Party. B. P. Mandal became Chief Minister of Bihar in 1967-68 for a short period before his Government was pulled down by supporting Congress Party for not rewinding the Commission appointed to inquire into allegations of corruption against Congress leaders during previous government.
The Mandals in Bihar belong to the Sadgop.
B. P. Mandal and his wife, Sita Mandal, were survived by five sons and two daughters. The third son, Maninder Kumar Mandal (popularly known as "Om jee"),and his son Nikhil Mandal in national and state politics.
The Government of India issued a stamp in honor of B. P. Mandal in 2001. A college named in his honor, B. P. Mandal Engineering College, was founded in 2007