Chatumongkol is a descendant of Thailand's royal family and belongs to the noble house of Sonakul. He was educated at Harrow School and is an honors graduate of Cambridge University in England for engineering and economics and Harvard University in John F. Kennedy School of Government. He rose up through the civil service through the Finance Ministry, initially serving as Director-General of the Tax Department. Later he rose to be the ministry's deputy permanent secretary. He was the permanent secretary in the Ministry of Finance from 1 October 1995 to 28 July 1997. This was during the flotation of the baht, which led to a massive devaluation, the Asian Financial Crisis, and a long period of International Monetary Fund intervention. He was dismissed by the Chavalit Yongchaiyudh government soon after the devaluation. During the Democrat-led government that followed, Chatumongkol was appointed Governor of the Bank of Thailand, Thailand's central bank. He held this position from 1998 to 30 May 2001, when he was dismissed by the newly elected Thai Rak Thai-led government. After his dismissal, Chatumongkol became a vocal critic of TRT leader Thaksin Shinawatra. He denigrated Thaksin's populist job-creating policies, claiming that "Any attempt to create petty jobs is unnecessary.... Policies should focus on providing machines and know-how." After a military junta overthrew Thaksin's government and cancelled scheduled general elections in 2006, Chatumongkol was one of its favorites for the Premiership; eventually General Surayud Chulanont was chosen by King Bhumibol. He hinted that if the Democrat Party won post-coup elections, he would enter the political arena in support of the Democrats. However, the Democrats were defeated in the elections. When the Democrat Party gained control of the government in 2008, it appointed Chatumongkol as Chairman of the Board of the Bank of Thailand. He noted that under Thaksin's populist policies, "people who got money did not think hard about how to use it. People who got motorcycles became motorcycle taxi drivers. Many got rich. But when more people became motorcycle taxi drivers, they ended up earning just 100 baht a day. I used to survey some of those drivers. Many said they would not vote for Thai Rak Thai party anymore."
