The founding of the Indonesian National Army is on the same date as the founding of the Indonesian Defense Forces. On 5th October 1945 the Government of the Republic of Indonesia issued a decree of the founding of a national army named People’s Security Army-formerly named People’s Security Body.

People’s Security Army had a mission to secure the state and people against armed disturbance from British soldiers and NICA – Netherlands Indies Civil Administration. At that time, the People Security Army as its core. People’s Security Army had possessed other forces, namely the Navy, Air Force and Police. In addition, People’s paramilitary units such as TRIP (Tentara Republik Indonesia Pelajar)/ Student Army of the Republic of Indonesia nand TP (Tentara Pelajar)/ Student Army and others, were founded as people’s resistance organizations to safeguard the 1945 independence of Indonesia.

Based on the Government Decree No. 2/SD dated 12 January 1946, People’s Rescue Army was changed into TKR (Tentara Keselamatan Rakyat)/ People’s Rescue Army with a mission to save the Republic of Indonesia with its people from being re-colonized.

Subsequently, on 25th January 1946 People’s Security Army was changed into TRI (Tentara Rakyat Indonesia) / Indonesian People’s Army which consisted of Army, Navy and Air force. On 5th May 1947, the President of the Republic of Indonesia amalgamated the armed paramilitary units into Indonesian People’s Army and the Army was named ADRI (Angkatan Darat Republik Indonesia)/ Republic of Indonesian Army. On later progression, in 1969, ADRI unified with ALRI (Navy), AURI (Air Force) and POLRI (Police) in order to form the Indonesian Armed Forces (Angkatan Bersenjata Republik Indonesian-ABRI), in which named of ADRI once again was altered to Indonesian National Army (TNIAD). Since 1st April 1999, along with the separation of Polri from ABRI, the Indonesian National Army, Navy and Air Force, are joined back as one armed forces, which is commanded by Panglima Tentara Indonesia (Chief of TNI).

Based on the Presidential Decree No. 163/1999 dated 14th December 1999, the National Army Valiant Day (Hari Juang Kartika) was declared on 15th December, On this date, the Indonesian National Army commemorates the Great Battle of Ambarawa in 1945 and take the unyielding battle spirits to be implemented in safe guarding the nation and the country.