Mr Fadanvis, who is 42, emerged as a consensus choice of the BJP's two Maharashtra factions led by former national president Nitin Gadkari and state-level strongman Gopinath Munde.
Mr Fadanvis is seen as close to neither group. He represents South West Nagpur in the state assembly and is known as a politician with a clean image.
"This is a huge responsibility. Our priorities will be those of the people of Maharashtra," he said.
Mr Fadanvis, a fierce critic of the ruling Congress-NCP, demanded that Maharashtra Deputy Chief Minister Ajit Pawar resign for making crass remarks against a farmer demanding water.
Listen to the latest songs, only on JioSaavn.com
Mr Fadanvis replaces the outgoing president, Sudhir Mungantiwar.