Mr Haasan, 62, made the announcement in the town of Madurai before crowds of his party supporters.
The state has a history of actors-turned-politicians - three have even served as chief ministers.
In December, Rajnikanth, another Tamil movie star, told his fans that he would form a political party before the next state election due in 2021.
Mr Haasan said in October he wanted to enter politics. His new party is called Makkal Needhi Mayyam, which roughly translated means Centre for People's Justice, the Press Trust of India reported.
He had said he would work towards becoming the state's chief minister so he can "right the wrongs of corruption and communalism" in the state.
Tamil Nadu has been politically unstable since the death last year of Chief Minister Jayalalithaa Jayaram, also a former film star.