Ajit Saini joined the British Indian Army where he was a lieutenant military officer. While fighting the Japanese army in the Malayan campaign, he came under the influence of Capt. Mohan Singh and thereafter defected to the Indian National Army in order to fight for India's liberation. His first job as part of INA was as the army's liaison officer for handling INA's communication with Japanese forces and diplomats. Thereafter he also worked as the assistant editor of INA news magazine Azad Hind which was published from Singapore.