The leader of the first Congress Ministry in Bihar was Shri Krishna Sinha.

Explanation:

The first Congress Ministry in Bihar was formed in 1937 after the Indian National Congress won the provincial elections. Shri Krishna Sinha, popularly known as Dr. Sri Krishna Sinha, was chosen as the leader of the Congress Ministry.

Background:
- Shri Krishna Sinha was a prominent leader of the Indian National Congress and played a crucial role in the Indian independence movement.
- He was born on October 21, 1887, in the district of Singhbhum, Bihar.
- Sinha became actively involved in politics during the non-cooperation movement led by Mahatma Gandhi.
- He was imprisoned several times for participating in the freedom struggle.

Leadership of Shri Krishna Sinha:
- After the Congress emerged as the largest party in the 1937 Bihar Legislative Assembly elections, Shri Krishna Sinha was appointed as the leader of the Congress Ministry.
- He became the first Chief Minister of Bihar and held the position from 1937 to 1939.
- During his tenure, Sinha implemented several progressive policies and initiated various welfare programs for the development of Bihar.
- He focused on education, agriculture, rural development, and infrastructure.
- He also worked towards improving the condition of Dalits and backward classes.
- Sinha played a significant role in shaping the socio-economic landscape of Bihar and worked towards reducing poverty and inequality.

Contributions:
- Shri Krishna Sinha was a strong advocate of land reforms and played a vital role in the implementation of the Bihar Tenancy Act, which aimed at providing security of tenure to tenants and protection of agricultural land.
- He also worked towards the implementation of the Zamindari Abolition Act, which abolished the feudal system and transferred ownership of land to the tillers.
- Sinha's efforts in the field of education led to the establishment of several schools and colleges in Bihar.
- He also played a crucial role in the formation of the All India States Peoples' Conference, which fought for the rights and welfare of the people in princely states.

Conclusion:
Shri Krishna Sinha's leadership as the first Chief Minister of Bihar was marked by his commitment to the welfare and development of the state. His progressive policies and contributions towards land reforms and education continue to have a lasting impact on the socio-economic fabric of Bihar.