He was one of the first volunteers to the First Indian National Army led by Mohan Singh, where he was appointed as commander of the Hindustan Field Force.

After this army collapsed due to disagreements with the Japanese, the Indian Independence League placed the remains of it under Mohammed Zaman Kiani as Army Commander and Bhonsle as Director of the Military Bureau, which was in charge of the general policy and finances of the INA.

After the formation of the second Indian National Army in 1943, led by Subhas Chandra Bose, Bhonsle became Chief of Staff and served in this position until the end of the war.

When Bose flew to Tokyo in August 1945, Bhonsle was left in charge of the INA in Bangkok, where he was captured by British forces.

He was the main proponent of the National Service Scheme, although he never lived to see it, for he would die 6 years before its establishment in 1969.