Ahmed was one of the founders of the Communist Party of India. In 1922, the Bharat Samyatantra Samiti was formed in Calcutta with Ahmed as its secretary. In 1924, he was sentenced to four years in prison because of his role in the Kanpur Bolshevik Conspiracy Case along with S.A. Dange, Nalini Gupta and Shaukat Usmani. He was released due to illness in 1925. In November, 1925 he, along with Kazi Nazrul Islam, Hemanta Kumar Sarkar, and others, organized the Labour Swaraj Party in Bengal. He was one of the main leaders of CPI in the early 1920's along with Abdul Halim and Abdur Rezzak Khan. , PC Joshi, Somnath Lahiri at Calcutta 1937 , Muzaffar Ahmed at Bengal Provincial Conference of CPI at Chandarnagore. On 20 March 1929, the British colonial government arrested 31 labour activists and sent them to Meerut for trial. Ahmed was the chief accused, along with S.A. Dange, Shaukat Usmani, P.C. Joshi and others, was convicted in this so-called Meerut Conspiracy Case. He was released in 1936. He had served the longest term in jail as the chief accused in the Meerut Trial. Prisoners taken outside the jail'''. Back row : K. N. Sehgal, S. S. Josh, H. L. Hutchinson, Shaukat Usmani, B. F. Bradley, A. Prasad, P. Spratt, G. Adhikari. Middle Row: R. R. Mitra, Gopen Chakravarti, Kishori Lal Ghosh, L. R. Kadam, D. R. Thengdi, Goura Shanker, S. Bannerjee, K. N. Joglekar, P. C. Joshi, Muzaffar Ahmed. Front Row: M. G. Desai, D. Goswami, R.S. Nimbkar, S.S. Mirajkar, S.A. Dange, S. V. Ghate, Gopal Basak. After the partition of India in 1947, Ahmed moved to Kolkata rather than staying in East Pakistan. On 25 March 1948, the Communist Party of India was banned by the Government of India and Ahmed was imprisoned. He was released from prison in 1951. He was again arrested and imprisoned for two years in 1962, and another time for two years in 1965. He was imprisoned several times in post-Independence India by the Congress government.
Personal life
Ahmed had a daughter, Nargis. She was married to the poet Abdul Quadir.
Death and legacy
Ahmed died in Calcutta in 1973, aged 84. The headquarters of the Communist Party of India in West Bengal is named after him. Also, Ripon Street, a thoroughfare in Kolkata, was renamed "Muzaffar Ahmad Street".