The deputy chief of the National Economic and Social Development Board will move up to become secretary-general Oct 1, succeeding new Transport Minister Arkhom Termpittayapaisith.
The cabinet on Tuesday promoted Porametee Vimolsiri to take over the agency when Mr Arkhom steps down at the end of this month.
Mr Arkhom is resigning from the top position at the policy to concentrate on transport issues at the ministry.
The cabinet also extended the tenure of cabinet secretary-general Ampon Kittiampon for another year.
Mr Ampon was appointed in 2010 after quitting as the NESDB chief.