[1][3] Sen was born in the island of Sandwip, off the coast of Chittagong, in the district of Noakhali, in a Bengali Hindu Kayastha family some time around 1909.

During his childhood he attended a normal school in the mainland, in the town of Chittagong.

[2] Sen played an active part during the Chittagong Armoury Raid.

He was sentenced to life imprisonment for his involvement in the incident and deported to the Andaman.

[2] According to Sandip Bandyopadhyay, Sen was drawn towards communism during his imprisonment and subsequently joined the Communist Party of India after his release.