Sothinathan has held various positions in MIC including that of Secretary-General and CWC member. He was the member of Parliament for Teluk Kemang (now known as Port Dickson) for two terms and also served as a Deputy Minister under the previous Barisan Nasional government.
About 2 days ago, the newly elected MIC President Tan Sri S.A.Vigneswaran removed 4 nominated CWC members, namely Dato S.Sothinathan, Datuk R.S.Maniam, Dato S.M.Muthu and James Kalimuthu from their respective positions and replaced them with Datuk Subramaniam (MIC Branch chairman from Klang Division), Datuk Nelson, Datuk Ravichandran and lawyer Murugavel who is also the chairman of MIC Shah Alam division.