Chuang was appointed "Chameun" Waiworanat, a high-ranking royal page. In Siamese–Vietnamese War (1841–1845), King Rama III commissioned Prince Isaret Rangsan and Chuang Bunnag to bring five Siamese rigged warships to attack Hà Tiên in January 1842. Prince Isaret Rangsan stayed at Phú Quốc and Chuang led the assault into Hà Tiên and sent Cambodian regiment to take Cô Tô mountain. After one week of bombardments, the reinforced Vietnamese did not yield. Prince Isaret Rangsan and Chuang Bunnag decided to retreat due to unfavorable winds.