Outgoing deputy prime minister Wissanu Krea-ngam said he will no longer be involved in politics after the new government takes office.
Mr Wissanu said on Friday he was packing up his belongings at Government House before moving out to make way for incoming cabinet ministers.
He said that after leaving office, he will spend time with his grandchildren at home, write books or work as a guest lecturer. He may also be invited to sit on companies' boards.
Mr Wissanu said he still works at the Office of the Council of State and the Office of the Royal Society.
"I will end my political role. I thought about this in 2006. But eight years later, an incident occurred and I had to get involved in politics again," he said, referring to the 2014 coup that ousted the Pheu Thai-led government.
"But this time, I hope that will not happen again. I also have some health issues," he said.
Mr Wissanu, 71, is a legal expert appointed as a deputy prime minister under the Prayut Chan-o-cha government after the 2014 coup.
He also served as a deputy prime minister during the Thaksin Shinawatra government between Oct 3, 2002 and June 24, 2006.
Asked to comment on the incoming government, he said: "I can't give any assessment as its make-up is not known yet.
"But as Srettha Thavisin got substantial support from MPs and senators [to become prime minister], I believe it will be strong and stable.
"However, there are 11 coalition allies and quarrels among them can be expected.
"If they can put the conflict behind them, this will benefit the government and the country.... Efforts to end political polarisation and work together for the country's best interests are a positive sign."