[10][11] His dissertation, The forms of the local performance development and promotion with image and identity in order to increase the value-added and value-creation: a case study of Phayao Province was "posted" in the European Journal according to Thamanat.

Forbidden to make photocopies, they translated a relevant court document into Thai as proof of the conviction that Thamanat continues to deny.

[22] Political activists have asked the Election Commission of Thailand (EC) to answer several Thamanat-related questions: how he managed to get reinstated in the army after his long stay in Australia in "state-sponsored accommodation"[23][24] and then got promoted in 1997 after returning to Thailand, and why he used the military rank of captain in documents he submitted to join the current cabinet even though his title was revoked in a Royal Thai Government Gazette announcement in September 1998.

In December 2019 he proposed spending 18 billion baht to purchase 30 million latex foam pillows to prop up rubber prices for struggling growers.

The chief of Thai Hua Rubber PLC, in favour of the idea, suggested that the pillows—estimated to cost 600 baht to manufacture—could be sold at low prices or given free to foreign tourists.

[28] On 9 September 2021, Thamanat was sacked from the cabinet after he had been accused of being behind a move to oust Prime Minister Prayut during the previous week's censure debate in parliament.

During the negotiations for the formation of the new cabinet, conflict emerged within Palang Pracharath between the factions of Thamanat and party leader Prawit over ministerial positions.

[33] This culminated in Pheu Thai's decision to remove Phalang Pracharath from the government coalition but still retaining the faction led by Thamanat, which obtained three cabinet seats.

[34] Thamanat's parliamentary declaration of assets in August 2019 listed two wives, four children, and a net worth of about A$42 million, including a Bentley, Rolls-Royce, Tesla, and Mercedes-Benz along with 12 Hermès and 13 Chanel handbags, luxury watches, and Thai Buddha amulets.