Formerly a warrior-prince who fought with distinction during his father's reign, upon his own ascension to the throne, Rajdhar showed little interest in such matters, instead becoming occupied with religious pursuits.

[8] Following the conquest of Noakhali and Chittagong by the Arakanese king Min Phalaung, Rajdhar, commanding a large contingent, was sent into the occupied regions to drive out the invaders.

[9] The army landed in Chittagong and Rajdhar, alongside his brother Amaradurlabha and the generals Chandradarpa-Narayan and Chattrajit Najir, led the capture of six enemy camps successively before halting at Ramu.

This forced the Tripuri to begin retreating back to Chittagong, though at the Karnaphuli River, they were attacked and defeated by the Arakanese, resulting in heavy casualties.

[11][12] With the Arakanese having abandoned the capital after their pillaging, Rajdhar returned and claimed his father's throne, adopting the traditional royal title of "Manikya".

Rajdhar was also considered notable for his great respect for Brahmins, participating in religious discussions with the 200 in his court and distributing significant amounts of land to them, in spite of opposition from his nobles.

[17] It is perhaps because of Rajdhar's devout manner that the ruler of Bengal invaded Tripura during this time, though the practical reason was likely to obtain access to the kingdom's elephants.