[4] The SID is led by a director, who holds the rank equivalent to a permanent secretary, and reports directly to the Prime Minister's Office (PMO).

After Singapore gained independence in 1965, the Ministry of Interior and Defence (MID) was directed to reorganise and consolidate all intelligence capabilities in January 1966.

[10] The SID was also mentioned in Lee Kuan Yew's book From Third World to First: The Singapore Story: 1965–2000, in which it is said to have played a role in providing weapons to anti-communist forces in Cambodian Civil War in the 1970s.

[10] Tim Huxley wrote a short history of the SID in his book Defending the Lion City: The Armed Forces of Singapore, which was published in 2000.

[13] In August 2013, it was alleged that the SID cooperated with the Australian Signals Directorate to tap the undersea fibre optic telecommunications cables that link Asia, Europe and the Middle East.