He received his formal education at Triam Udom Suksa School and graduated from Chula Chom Klao Army Cadet Academy, in 1949. Then, he went through Army Communication School, Fort Bournemouth, United States of America, Army Regiment IX, Ryukyu Island, Okinawa, Japan, Army Communication School, Thailand, Army Command and General Staff College, both in Thailand and in United States of America, NOVICE Paratroopers School (Outstanding Medal: General Staff Course), United States of America, Pepperdine University (Honorary Doctorate in Laws; 1987), United States of America, and Srinakarinwirot University (Honorary Doctorate in Arts).

He first served the Royal Thai Army, as Acting Second Lieutenant, in 1954, and was appointed Platoon Leader of Army Communication Maintenance Department, in 1963. Then, in 1971, he was promoted to Head of Army Operations Division and, in 1980, to Director-General of the Army Operations Department. In 1985, he was appointed Army Chief of Staff and, in 1986, was promoted toCommander-in-Chief of the Royal Thai Army. Finally, in 1987, he was promoted to Commander-in-Chief of the Supreme Command Headquarters.

General Chavalit Yongchaiyudh started his political career, as Deputy Prime Minister and Minister of Defense, during the term of General Chatichai Junhavan, in 1988. He was later appointed Minister of Interior, in 1992 to 1994, Deputy Prime Minister and Minister of Defense, in 1995 to 1996. In late 1996, following the Royal Decree of Parliament Closure, the General Election was held.

On November 17, 1996, New Aspiration Party, of which General Chavalit Yongchaiyudh was leader, won the most seats and its leader became Prime Minister, with the approval of six coalition parties, namely New Aspiration, Chart Pattana, Social Action, Thai Citizen, Seri Dhamma, and Mass Citizen.

He was appointed 22nd Prime Minister, by Royal Decree of King Rama IX, on November 25, 1996. Once in office, he encountered pressure from many political movements which, coinciding with the increasing economic problem, forced him to resign. Finally, he left office on November 6, 1997, when the economic crisis had its final blow on Thailand and the unrest spread over.