Edappadi K Palaniswami, the leader of the AIADMK Legislature Party, took oath as Tamil Nadu Chief Minister. He heads a 31-member Cabinet.
He was administered oath of office and secrecy by the Tamil Nadu Governor, Vidyasagar Rao.
Palaniswami has been given 15 days to prove his majority.
He took over as the leader of AIADMK Legislature Party from VK Sasikala, after she was convicted in a corruption case and ordered to be imprisoned for four years. She surrendered on Wednesday at the Special Court in Bengaluru and was jailed.