During the Indonesian National Revolution, Simatupang, now a colonel, joined the Siliwangi Division in Central Java, and by January 1950, following the death of General Sudirman, he was acting chief of staff of the Indonesian Armed Forces. Like army chief of staffGeneral Nasution, he was an "administrator", committed to the reduction in size of the armed forces after independence had been won in order to bring about a professional military. He opposed efforts by a disgruntled rival, Colonel Bambang Supemo, to replace Nasution, but was himself criticized for apparent political bias after articles he wrote in 1952 were perceived as favoring the Socialist Party of Indonesia. After the incident on 17 October 1952, in which the army brought demonstrators and troops to the Merdeka Palace in an effort to persuade President Sukarno to dissolve parliament, Simatupang's days were numbered, and on 4 November 1953, his post as chief of staff was abolished, effectively dismissing him. He then took a position as an adviser to the Ministry of Defense, and then became a lecturer at the Army Staff College and the Military Legal Academy before resigning from the military altogether in 1959.
Pemerintah, masjarakat, Angkatan Perang. Pidatopidato dan karangan-karangan 1955-1958
Laporan dari Banaran : kisah pengalaman seorang pradjurit selama perang Released in English in 1972 as Report from Banaran: Experiences during the people's war, translated by Benedict Anderson, E. Graves, John Smail. Released in Dutch language in 1985 as Het laatste jaar van de Indonesische vrijheidsstrijd, 1948-1949 : een authentiek verslag door de voormalig chef-staf van de Indonesische strijdkrachten
Capita selecta masalah hankam T.B. Simatupang
Pembangunan : soal hidup atau mati bagi negara Pantjasila
Pengantar ilmu perang di Indonesia
Komunikasi, konfrontasi, modernisasi dan negara Pancasila yang membangun
Kejakinan dan perdjuangan
Dari Edinburgh ke Jakarta
Ketahanan nasional dalam situasi baru di Asia Tenggara
Het laatste jaar van de Indonesische vrijheidsstrijd, 1948-1949 : een authentiek verslag door de voormalig chef-staf van de Indonesische strijdkrachten
Harapan, keprihatinan dan tekad; Angkatan 45 merampungkan tugas sejarahnya.
Kehadiran Kristen dalam perang, revolusi, dan pembangunan : berjuang mengamalkan Pancasila dalam terang iman
Membuktikan ketidakbenaran suatu mitos : menelusuri makna seorang prajurit generasi pembebas bagi masa depan masyarakat, bangsa dan negara Released in English in 1996 as The fallacy of a myth