Sinha is a member of the Indian National Congress Party, having joined them after he was not given a seat for the 2019 Indian general elections by the Bharatiya Janata Party. He entered politics by contesting in a by-election opposite Rajesh Khanna. Sinha quoted in an interview that his biggest regret in his life was contesting election against his friend Khanna. Khanna won the elections by beating Sinha by 25,000 votes; however, he was hurt and never spoke to Sinha thereafter. Sinha did try to rebuild his friendship with Khanna; however, that never happened till Khanna's death in 2012.