Thackeray was blamed for aggravating tensions between Hindus and Muslims during riots two decades ago in Mumbai, the BBC reported, although he was never convicted of any wrongdoing in the riots.
Thackeray founded the political organization Shiv Sena with the purpose of favoring indigenous residents of Maharashtra state over migrants and to stall the spread of Islam.
He suffered cardiac arrest about 3:30 p.m. local time, said his physician, Dr. Jalil Parkar, reported Press Trust of India.
Thackeray had been suffering from breathing problems and pancreatic disease.
A cartoonist by training, he formed Shiv Sena in 1966 to further the political agenda of his magazine, in which he highlighted what he considered biases against hiring "sons of the soil," the Hindustan Times reported.
By 1973 the organization had become a potent force in Mumbai politics. In 1995, Sena allied with the BJP party to take power in the Indian congress.
Thackeray had encouraged Hindus to form suicide attacks against Muslims. A government investigation said Shiv Sena was largely responsible for organizing attacks on Muslims during riots in Mumbai in 1992 and 1993.
Survivors include sons Jaidev and Uddhav.