As of 2023[update], it comprises approximately 400,000 military personnel including the Indonesian Marine Corps (Korps Marinir RI), which is a branch of the Navy.

Next to Dutch volunteers and European mercenaries, the KNIL also recruited indigenous, especially Ambonese, Kai Islanders, Timorese, and Minahasan people.

[10][clarification needed] Some of the indigenous soldiers that had enjoyed Dutch KNIL military academy education would later become important TNI officers, for example Suharto and Abdul Haris Nasution.

Indonesian nationalism and militarism started to gain momentum and support in World War II during the Japanese occupation of the Dutch East Indies.

On 3 October 1943, the Japanese military formed the Indonesian volunteer army called PETA (Pembela Tanah Air; Defenders of the Homeland).

Many of these men who served in PETA, both officers and NCOs alike like Sudirman, formed the majority of the personnel that would compose the future armed forces.

The Indonesian Armed Forces started out as the People's Security Agency (Badan Keamanan Rakyat, BKR), which was formed in the third PPKI meeting, on 29 August 1945.

BKR united militias across the newly independent country to maintain civil order; it was more of a constabulary than an army.

One of the terms of surrender to Japan was to return the Asian colonies they had conquered to their previous rulers, certainly not to make them independent.

Their first conflict was the 1945–1949 Indonesian National Revolution, in which the 1945 Battle of Surabaya was especially important as the baptism of fire of the young armed forces.

After the fall of Suharto in 1998, the democratic and civil movement grew against the acute military role and involvements in Indonesian politics.

The reforms also involved law enforcement in common civil society, which questioned the position of Indonesian police under the military corps umbrella.

In April 1999, the Indonesian National Police officially regained its independence and now is a separate entity from the armed forces proper.

[18] The Indonesian military philosophy about the defense of the archipelago is summarily civilian-military defence, called "Total People's Defense", consisting of a three-stage war: a short initial period in which an invader would defeat a conventional Indonesian military, a long period of territorial guerrilla warfare followed by a final stage of expulsion, with the military acting as a rallying point for defense from grass-roots village level upwards.

The doctrine relies on a close bond between villager and soldier to encourage the support of the entire population and enable the armed forces to manage all war-related resources.

The current developments in Indonesia's defense policies are framed within the concept of achieving "Minimum Essential Force" or MEF by 2024.

It was only after the attempted coup d'état of 1 October 1965 and General Suharto's rise to the presidency that it became possible to integrate the armed forces and begin to develop a joint operations structure.

Following a decision in 1985, major reorganization separate the Ministry of Defense and Security from the ABRI (Angkatan Bersenjata Republik Indonesia, the name of the armed forces used during the New Order) headquarters and staff.

[22] MoDS was made responsible for planning, acquisition, and management tasks but had no command or control of troop units.

The former territorial commands of the air force and navy were eliminated from the structure altogether, with each of those services represented on the "Kodam" staff by a senior liaison officer.

[29] In July 2019, President Widodo officially formed the Armed Forces Special Operations Command (Koopsus TNI) which comprised 400 personnel each from Sat-81 Gultor of Kopassus, Denjaka, and Den Bravo of Kopasgat to conduct special operations to protect national interests within or outside Indonesian territory.

The Seven Commitments is a pledge of loyalty and fidelity of the military personnel to the government and people of Indonesia and to the principles of nationhood.