Ambassador Toan was born in Thanh Hoa in 1952 and holds a Master of Arts in International Relations.

His professional career is as follows:

• 2006: Executive Director, Asia-Pacific Economic Cooperation Secretariat
• 2005: Deputy Executive Director, Asia-Pacific Economic Cooperation Secretariat
• 2003–2004: Director General, Foreign Minister's Advisory Board, then Director General, Department of Multilateral Economic Cooperation, Ministry of Foreign Affairs
• 2000–2003: Ambassador of the Socialist Republic of Viet Nam to Malaysia
• 1999: Viet Nam Senior Official to APEC
• 1996–2000: Director General, Department of Economic Affairs, Ministry of Foreign Affairs; Vice Chairman, Vietnam National Committee for the Pacific Economic Cooperation Council (PECC)
• 1992–1995: Minister Counsellor, Embassy of Viet Nam, New Delhi, India
• 1990–1992: Acting Director General, South Asia Department, Ministry of Foreign Affairs
• 1984–1989: Official, Foreign Ministry's Secretariat and Assistant Director, Foreign Ministry's Secretariat
• 1980–1983: Official, Embassy of Viet Nam, New Delhi, India