[6][7] In 2010 he was also elected as Member of Legislative assembly of the Baisi (Vidhan Sabha constituency) of Purnea district as a Bharatiya Janata Party candidate.

[8][9][10] Born to Nevilal Vishwash and Ramsakhi Devi in 1976, Santosh's education was completed in Purnea from Surya Narayan Singh college, Rambagh.

He defeated Uday Singh Pappu in 2019 Lok Sabha elections with a large margin of over 2.5 Lakh votes.

[14] In 2024 Indian General Elections, Kushwaha was repeated as the candidate of National Democratic Alliance from Purnia Lok Sabha constituency.

[15] Kushwaha was allegedly involved in helping Awadhesh Mandal, the husband of Janata Dal (United) Member of Legislative Assembly, Beema Bharti to escape from police custody in Purnia.