Regarded to be one of India's most influential regional people of the time, his reputation was synonymous with being a strict disciplinarian and tough taskmaster.

[8] His father was a nationalist leader, Dr. Anugrah Narayan Sinha, who closely assisted Mahatma Gandhi[9] along with Dr.Rajendra Prasad in the Champaran Satyagraha movement,[10] the first satyagraha movement in the country and also served as the[11] first Deputy Chief Minister cum Finance Minister of the Indian state of Bihar.

He was part of the young Turk brigade of the Indian National Congress party during the time of the first Prime Minister of India[13] Jawaharlal Nehru.

As the state education minister, he played an instrumental role in the establishment of Magadh University in Bodh Gaya, in the year 1962.

He occupied the second position[13] (second-in-command) in the Cabinet and played the role of a de facto Chief Minister during the period 1961–1967 under the Governments headed by K. B. Sahay and Pandit Binodanand Jha.

He had[13] a unique political acumen to determine the electoral prospects of candidates in assembly election by just sitting at home in Patna.

S. N. Sinha also played a key role in the installations of Governments headed by chief ministers Krishana Ballabh Sahay, Satish Prasad Singh, B.P.

"Chhote Saheb, as he was popularly called, was an important political leader of Bihar, a distinguished Parliamentarian, and someone who had the interests of his state and people uppermost in his mind.

During his long public life of over six decades, Sinha Ji made significant contributions in streamlining the education system of Bihar."

"I believe in participative democracy and not dictatorial attitudes" " He was a great humanitarian and an educationist who changed the face of education in Bihar by his radical and innovative ideas that were far ahead of their time.

The state owes a lot to him.." He is also credited for the[29] establishment of the Indira Gandhi Planetarium cum Science Centre in Patna.

In his autobiography Meri Yaadein, Meri Bhoolein, released by the then Bihar Governor Buta Singh in the presence of Defence Minister Pranab Mukherjee (also former President of India), He accused his state colleagues of "fanning" the 1989 Bhagalpur violence to malign him, specifically mentioning his predecessor and former chief minister Bhagwat Jha Azad and the former speaker Shivchandra Jha.

He didn't agree with the over-ruling of his order to transfer the then superintendent of police K S Dwivedi who had failed miserably to discharge his duties.

The decision was not only an encroachment of the Constitutional right of the state government but also a step detrimental to ongoing efforts to ease tensions.

The riots are said to have claimed the lives of thousands of Muslims, mostly poor weavers, while the police and Congress administration under Sinha took no action.