Dasmunsi signing an Agreement on "Indo-UK Film Co-operation" in New Delhi, December 5, 2005.Dasmunsi addressing at the inauguration of the Indian Panorama during the 37th International Film Festival (IFFI) in Panaji, Goa, November 24, 2006.
Dasmushi entered politics as a member of the Chhatra Parishad, the student's wing of the state Congress unit while studying in the Calcutta University as a protégé of veteran Congress leader Atulya Ghosh when the state was hit with the first-wave of Naxalite-Maoist insurgency, which saw large number of students from well-reputed colleges & universities of Calcutta abandon their studies to take up arms against the state in lines of the people's war strategy of Naxalite ideologue Charu Majumdar. He, alongside Subrata Mukherjee & Somen Mitra was the prominent militant face of the Chhatra Parishad who clashed heads-on with the student cadres of both CPI(M) & CPI(ML) alike in the politically turbulent atmosphere of the state caused by a fractured mandate in the state elections & the Naxalite insurgents.[1] Known for his organisational capability, fiery speeches & strong anti-Communist stance, Dasmunshi was violently assaulted by CPI(M) cadres in 1967 after a street rally in the suburbs of North Calcutta, which left him with a fractured arm, thereby cementing his image as a firebrand anti-Communist leader.[2] Dasmunsi was made state president of Indian Youth Congress in from 1970 to 1971. He was elected from the South Calcutta constituency in the 1971 Indian general election at the age of 26, defeating veteran Communist leader & freedom fighter Ganesh Ghosh. He lost the seat to Janata Party candidate Dilip Chakravarty in the next general election. After having a fallout with Sanjay Gandhi, Dasmunshi joined the Congress(Urs) of D. Devraj Urs in 1978. Following him coming 4th in the South Calcutta constituency during the 1980 Indian general election & the dismal performance of the party in 1982 state election, he returned back to the Congress(I) in 1984 after Indira Gandhi's murder. He was appointed as the Union Minister of State for Commerce in 1985 by prime minister Rajiv Gandhi after being elected from the Howrah constituency promising re-industrialisation of the area. But his failure to keep his electoral promise saw him lose the seat in the 1989 general election. He also led a fiery campaign against the CPI(M)-led Left Front government of the state in 1987 state election as the state PCC chief, but failed to dislodge the Communists. He again lost from Howrah in 1991, but was re-elected back from there in 1996. From 1999, he was the MP from Raiganj constituency
Since Dasmunsi's hospitalization, his wife Deepa, to some extent had taken over his political mantle; she was elected from Raiganj (Lok Sabha constituency) in 2009.
On 10 October 2011, the Indraprastha Apollo Hospital in Delhi advised his family to take him home and care for him there.[12]
After lingering for nine years in coma, Dasmunsi finally died on 20 November 2017, a week after his 72nd birthday. His dead body was taken to Kaliaganj and was cremated at the local crematorium.[13]