After completing his education, Panggabean took on work as a teacher, an occupation held in high regard in the Batak community, and even became the principal of a school in Tarutung.

In Panggabean's case however, he seemed to have only manage to go through military schooling and basic training before the Japanese surrendered and nationalist leaders Sukarno and Mohammad Hatta proclaimed Indonesia's independence.

Like all other youths all around Indonesia, Panggabean was caught up in the rush to take weapons from the Japanese in preparation of the formation of a National Army.

On 5 October 1945, the People's Security Army, the precursor to the Indonesian National Armed Forces and later on, TNI[clarification needed] was formed.

Panggabean took up the position of military trainer at Sibolga before serving as Chief of Staff for the 1st Battalion, 4th Regiment, 10th Division in Sumatra until 1949.

Following the Indonesian National Revolution of 1945–1950, Panggabean spent the next 10 years as a regimental chief of staff at Tapanuli and as a sectoral commander in the Military Territory of North Sumatra.

Two years later, in 1971, Suharto reshuffled the Cabinet and Panggabean became Deputy Commander in addition to becoming State Minister assisting the President in matters of Defense and Security.

[3] Panggabean reached the pinnacle of his military career in 1973 when he became Commander of the Indonesian National Armed Forces in addition to becoming Minister of Defense and Security.

In 1989, he became a Patron of the Bona Pasogit Foundation, an organization dealing with the rehabilitation of earthquake-affected areas in Panggabean's native Tarutung.