Gen Thitiwat Kamlang-ek nominated Thinnaphan to the post during the first meeting of the NRSA chaired by Chai Chidchob in his capacity as the most senior NRSA member.
Without other candidates, Thinnaphan won the top post of the assembly.
The assembly also elected Alongkorn Pollabutr and Walairat Sri-aroon as the first and second vice president of the assembly.
Thinnaphan thanked NRSA members of trusting him to the post.
He said he would follow up on the reform proposals of the defunct National Reform Council.
Thinnaphan asked NRSA members to be united so that the works of the assembly would be successful.
The first meeting of the NRSA was closed at 11:10 am.