He graduated from Gadjah Mada University before joining the Indonesian Department of Foreign Affairs in 1982.
After completing the department's course for junior diplomats in 1984, he took on a role promoting international environmental preservation.
Speaking about on his time in Australia at the end of the posting in 2005, Cotan reflected that the relationship was difficult when he first came to Canberra in 2003 because of events that happened in East Timor in 1999.
[2] Cotan said the aid and relief Australia's military had provided to Indonesia in the wake of the 2004 Indian Ocean earthquake and tsunami had brought the two countries closer.
[4] While he was ambassador, the Indonesian Government opened a consulate general in Shanghai, which was expected to enhance the ties between the two nations.