After a successful career in the military which saw him rise to Supreme Command chief of staff in 1961, he turned to politics and was appointed deputy defense minister in 1963.

Flight Lieutenant Dawee was a member of the last Thai military mission to Malaya in October 1941, and returned just days before the commencement of the Pacific War.

At 08:00 on 8 December 1941, Flight Lieutenant Dawee Chullasapya and Pilot Officer Sangwaan Worasap rushed off in their Hawk 75Ns to pursue a lone Japanese reconnaissance plane cruising in the skies above Don Mueang.

Dawee was to make the journey with three Americans: two OSS officers, Majors John Wester and Howard Palmer; and the Flying Tigers' "Black Mac" McGarry, who since being shot down in the Chiang Mai area in January 1942 had been in a POW camp.

The party arrived in Madras some hours later, and Dawee continued on to Colombo, where he met Sanguan Tularak, a fellow Seri Thai agent.

The sojourn in Ceylonese capital did not last long, however, as the Wing Commander was taken by Colonel John Coughlin of the OSS to meet Lord Mountbatten at Kandy.

Dawee was to collect intelligence regarding Japanese troop dispositions, and to aid in the establishment of secret airfields for which the Allies could fly in agents and supplies to reinforce the Seri Thai.

The Wing Commander immediately reported back to Pridi's new residence at the Bang Pa-In Summer Palace, approximately 70 km north of Bangkok.

Dawee returned to Calcutta to pick up OSS Major Nicol Smith and Lloyd George, a civilian reports officer, and to bring them to Bangkok for direct talks with Pridi.

Dawee supervised the creation of a massive arms cache in the many classrooms of Thammasat University, and returned to Calcutta on 10 August, where he celebrated the end of the war with the staff of SEAC.

Dawee accompanied Seni Pramoj back to Bangkok on September 16, and returned permanently on December 5, 1945, escorting the young King Ananda Mahidol.

"[2] After Thailand had received a new constitution in 1968, Dawee joined the United Thai People's Party, created by military leaders Thanom Kittikachorn and Praphas Charusathien in order to continue their rule under the guise of parliamentary system.