Vietnam's Ambassador to Indonesia Hoang Anh Tuan was appointed Deputy Secretary General of ASEAN at the grouping's Coordinating Council meeting in Manila, the Philippines on Sunday.
Tuan will be in charge of the bloc's political and security affairs from February 2018 to February 2021.
"I will try my best not to disappoint anyone," Tuan wrote on his Facebook page. "I will try my best to build an inclusive ASEAN Secretariat, to represent ASEAN's efforts to build a common home and an ASEAN community for peace, consolidation, integration and prosperity."
At the 16th meeting of the ASEAN Political-Security Community council, ASEAN Secretary General Le Luong Minh, who is also a Vietnamese career diplomat, also reported on cooperation within the community this year, as well as complicated regional and international affairs that affect ASEAN.
The 31st ASEAN Summit follows the conclusion of the 2017 Asia-Pacific Economic Cooperation Summit in the central Vietnamese city of Da Nang, which was attended by leaders of the 21 economies, including the U.S., China and Russia.
During Tuan's tenure as Vietnam's ambassador to Indonesia, he has helped resolve many issues concerning Vietnamese fishermen captured by Indonesia.
The current ASEAN Secretary General, Le Luong Minh, was the first Vietnamese diplomat to be appointed to the role, which he will step down from next month.