On 20 July 1937, he became the Premier of Bihar province when Congress came to power. Under the Government of India Act of 1935, Sinha formed his Cabinet at Patna on 20 July 1937. He and his colleague A.N. Sinha disagreed with the governor on the issue of the release of political prisoners and resigned. The then-governor had to accede to the demands for release of prisoners from Cellular Jail (Kalapani) and Bihar Tenancy Act was reformed in favour of peasants. They then resumed office. But they again resigned in 1939, as did all Congress chief ministers, over the question of involving India in the Second World War without the consent of the Indian people. Along with A.N. Sinha,the first deputy chief minister cum finance minister of Bihar, he is considered one of the makers of modern Bihar.