[5] In 2004, the state-owned Krung Thai Bank (KTB) shocked Thailand's financial world by reclassifying approximately 40 billion baht as problem loans.

Viroj was a former financial advisor to media proprietor Sondhi Limthongkul, having helped him make the initial public offering of one of his first companies.

[7] As Krung Thai Bank head, Viroj had forgiven 1.6 billion baht of Sondhi's debts and arranged for further rounds of forgiveness.

Sondhi's public criticism of Thaksin started to increase, eventually leading to the establishment of the People's Alliance for Democracy.

[8] Two days after the coup which deposed Prime Minister Thaksin Shinawatra, the Bangkok newspaper The Nation reported that business leaders had asked the junta (Council for Democratic Reform under Constitutional Monarchy) to appoint Pridiyathorn as an interim prime minister.

As a reason for his resignation he cited Premier Surayud's decision to appoint Pridiyathorn's rival, former Thaksin-government Finance Minister Somkid Jatusripitak, as a "self-sufficiency economy" special envoy.

The Bangkok Post reported that Pridiyathorn resigned in protest after a CNS member lobbied him to sell shares of IRPC (formerly known as Thai Petrochemical Industry or TPI) back to a former shareholder.

Saprang's brother, Chienchuan, was a key financial advisor to Prachai Liaophairat, the estranged founder of TPI.

[28][29] Pridiyathorn was an outspoken critic of Yingluck Shinawatra's government, especially its scheme assuring a fixed minimum rice price to farmers.

[33] After the 22 May 2014 coup d'état, the junta—which calls itself National Council for Peace and Order—appointed Somkid a member of its "advisory board" in charge of economic issues.

[34] On 31 August Pridiyathorn was appointed a deputy prime minister in the first military-appointed cabinet under General Prayut Chan-o-cha.