The role of the king as chief warrior was derived from Hindu concepts of kshatriya, and later much influenced by the ideal of a chakravartin as defender of the realm.

This martial responsibility has by tradition been borne by every Thai monarch since, but has never been formally instituted.

After the end of the absolute monarchy in 1932, Siam's first permanent constitution established the ceremonial role of Head of the Siamese Armed Forces (จอมทัพสยาม; Chom Thap Sayam) in Article 1, Section 5.

The king participates in military activities and functions, including the presentation of ceremonial colours, based on the national flag, to various units of the armed forces and the presentation of ceremonial swords to all graduating officers of the military academies.

The armed forces celebrate the king with an annual parade held on his birthday at the Royal Plaza in central Bangkok.