[1] His ancestors were originally from Present-day Tamil Nadu, who settled in Bengal in 16th century.
The son of Kanai Lal Acharia and Konak Lata Acharia, he was born in Bero village of Raghunathpur I block in Purulia district to a family of Tamil Brahmins, who had once migrated to the village during the 16th century as the royal priests of Garh Panchkot under the Panchkot Raj family.
After completing his MA from Ranchi University, he started his career as a school teacher.
[2] In 1980, he was nominated as the CPIM candidate for the 1980 Indian general election from the Bankura constituency after Biman Bose, initially party's first choice as the candidate, opted out due to his preference in organisational activities instead of parliamentary politics and instead proposed Acharia's name to the party as a potential candidate.
[3] Acharia was elected for the first time as a member of the 7th Lok Sabha from Bankura constituency in 1980.
From 1985 until his death, he was a member of the CPI(M) West Bengal State Committee.
Acharia was elected as leader of the CPI (M) Parliamentary Party in the 14th Lok Sabha in 2004 after Somnath Chatterjee was elected as Lok Sabha Speaker.
In 2009, he was re-elected as the leader of the CPI (M) Parliamentary Party in the 15th Lok Sabha.
During 2018 Panchayat elections he was attacked by the Trinamool Congress and was left bloodied and injured while leading a procession with candidates for filing nomination at the BDO office of Kashipur in Purulia district.