[4] Mitra joined in the Non-cooperation movement while taking his Master of Arts degree in the University of Calcutta.
He went to Etawah with his friend another revolutionary Bankim Mukherjee to organise grass route people in support of Gandhism.
After release Mitra personally met with Mahatma Gandhi at Sabarmati Ashram and worked with him continuously three years.
[4] After that he participated in trade union movements, constructed labour organisation in various area of West Bengal.
Police again arrested Mitra in Meerat Conspiracy Case but he was released by order of Allahabad High Court.