The 1st Infantry Battalion of the 21st Regimental Combat Team[5] was formed on 22 September 1950 by the regent, Rangsit Prayurasakdi, under executive of Prime Minister Plaek Phibunsongkhram, at the request of United Nations Command (UNC).

Trainee must serve in the 21st Regiment Queen's Guard or be permitted by the Royal Thai Army to attend training.

Those who successfully complete the tiger training course receive a military capabilities plate from the queen.

In the 1990s, according to one academic, "...the Eastern Tigers amassed considerable wealth by trading gems with Cambodian Khmer Rouge insurgents based along the two countries' border, a racket which 'directly benefited'... some of its commanders.

Former Queen's Guard commanders led the May 2014 Thai coup d'état that toppled the elected government.