Born 27 August 1951 in Pematangsiantar, North Sumatra, he first studied law in Medan and Yogyakarta and received a bachelor's degree in law, but later followed his main interest and earned a bachelor's degree in archaeology in 1979 at Gajah Mada University.
His post-graduate studies brought him to the Institut de paléontologie humaine [fr] in Paris, where he obtained a master's degree in 1987 and a Ph.D. in 1991.
He studied archaic human remains from the Paleolithic in Jawa, Sumatera, Kalimatan, Sumba, and the Maluku Islands.
[5][3] According to Truman Simanjuntak, the Indonesian archipelago has harbored a wide cultural diversity from prehistorical times until now.
[4] Based on archaeological evidence from distinct pottery styles, he proposes a two-way entry of the Neolithic populations of western Indonesia: the Eastern Route Migration from the northeast, connected to the Austronesian expansion, and the Western Route Migration from the northwest from Mainland Southeast Asia.