He is best known for being one of Indonesia's representatives at the UN security session held on August 14, 1947, together with Soedjatmoko, Soemitro Djojohadikusumo, Sutan Sjahrir, H. Agus Salim, and L. N. Palar.

The arrival of Charles Tambu went to the Dutch East Indies because he joined his father and mother who migrated in search of a better life.

In the Merdeka magazine entitled, " Charles Tambu: Turunan Asing Tapi Djiwanya Indonesia", (No.

II, October 22, 1949) mentions Charles Tambu, a former illegal immigrant from Sri Lanka, who steadfastly and sincerely defended Indonesian sovereignty at the United Nations in 1947.

Tambu’s former co-worker Mochtar Lubis was instrumental in setting up this newspaper in 1952 and was himself the editor-in-chief of ‘Indonesia Raya’.