SIMI was formed by a group of Muslim students, originally as an offshoot of Jamaat-e-Islami Hind (JeIH). It was established on April 25, 1977 at Aligarh. The organization has declared itself to be against Hinduism, western thought and other non-Islamic influences they see as contributing to immorality. Its members considers themselves in a jihad against these influences in India.
Until it was banned, the organization was led by its president, Dr Shahid Badar Falah, and its secretary-general, Safdar Nagori. Both ran into legal problems before the ban: Falah was arrested on September 28, 2001, and charged with sedition and "inciting communal disharmony"; Nagori fled on September 27 and has been a fugitive since.
Before it was banned, the organisation published several periodicals, which were condemned by the government for exacerbating Hindu-Muslim tensions. Since the ban, and largely as a result of the arrest of many of its prominent members, it has largely disappeared from public life, but is rumored to be operating underground under the control of Nagori. There are reports it has established links with terrorist groups in Bangladesh and Pakistan, and also charges that several other regional, still-legal Islamist groups in India are controlled by former SIMI members, including the National Democratic Front and Islamic Youth Centre (IYC), and the Tamil Nadu Muslim Munnetra Kazhagam (TNMMK).