Nakharin Mektrairat has been named the Constitutional Court president to succeed Worawit Kangsasitiam, who vacated the post on Sept 9 last year.
Mr Nakharin was selected among nine judges with five votes. Jiraniti Hawanont and Panya Udchachon received two votes each.
Appointed under the 2007 constitution, Mr Nakharin has been a Constitutional Court judge since November 2015. His nine-year term will end in November but could be extended.
Before being appointed a Constitutional Court judge, he was a lecturer at Thammasat University's political science faculty, serving part of that as faculty dean from February 2004 to January 2010. He also took part in the charter writing process during 2006-2007 and 2014-2015.
The 66-year-old is a political science graduate from Thammasat University with a master's degree in history from Chulalongkorn University and a doctorate in international studies from Japan's Waseda University.
He was one of the three minority judges who ruled that former prime minister Prayut Chan-o-cha's eight-year tenure ended on Aug 24, 2022.
He was among the majority of judges who accepted a petition involving former Move Forward Party (MFP) leader Pita Limjaroenrat's MP status, resulting in Mr Pita being suspended from his MP duties.
The selection of the new president comes ahead of three key cases to be ruled this month.
On Jan 17, the court is scheduled to issue a ruling in a case against Bhumjaithai Party secretary-general Saksayam Chidchob, who stands accused of concealing assets and using a nominee to hide ownership of a company which won government construction projects.
On Jan 24, the court is set to rule on the fate of Mr Pita, now the advisory chairman of the main opposition party, who is accused of violating a media share-holding rule concerning his running in last year's general election.
On Jan 31, the court will rule whether the MFP's policy on Section 112 of the Criminal Code, better known as the lese majeste law, was an attempt to overthrow the constitutional monarchy.
On Wednesday, the court issued an announcement to ensure public order for those three dates, saying only the individuals directly involved in the cases or authorised individuals are allowed in the courtroom to hear the rulings.
