[1] A veteran leader of the Communist Party of India (Marxist), Radhakrishnan previously served as a State Minister of Kerala from 2021 to 2024, and from 1996 to 2001.

He was an active member in SFI, holding posts like unit secretary of Sree Kerala Varma College, Chelakkara area secretary, and member of Thrissur district secretariat as an SFI leader.

Radhakrishnan was elected to the Thrissur District Council in 1991 from the Vallathol Nagar division.

He served as Minister for the Welfare of Backward and Scheduled Communities and Youth Affairs from 1996 to 2001.

[2] • SFI Unit Secretary,Sree kerala varma college Thrissur • DYFI State committee member • Member, District Council, Thrissur from Vallathol Nagar Division • Member of Legislative Assembly, Chelakkara Assembly constituency 1996, 2001, 2006, 2011, 2021 • Minister for Welfare of Scheduled Castes &Tribes, Backward classes, Youth Affairs Nayanar Ministry 1996 - 2001 • Member District Committee, CPI(M) Thrissur • Opposition Chief Whip, Kerala Legislative Assembly 2001-06 • Member CPI(M) District Secretariat, Thrissur • Member CPI(M) State committee • Speaker, Kerala Legislative Assembly 2006-11 • District Secretary CPI(M) Thrissur 2016 -18 • District Convenor, LDF Thrissur 2012-18 • State President, Pattikajathi Kshema Samithi (PKS) • State President Farm Workers Union (CITU) • State President, Kerala Clay Pottery Workers Union • Central Committee member CPI(M) 2018 onwards • All India President, Dalit Shoshan Mukti Manch (DSMM) • Minister for Devaswoms, Welfare Scheduled Castes & Tribes, Backward Classes, Parliamentary Affairs 2021-2024 Pinarayi Vijayan Ministry • Member of Parliament, Alathur Loksabha • Parliamentary Party Leader of CPI(M), Lok Sabha • Member,Joint Parliamentary Committee (JPC) on 'One Nation One Election' Bill- The Constitution (One Hundred and Twenty-Ninth Amendment) Bill, 2024.