O Paneerselvam was born on January 14, 1951 at Periyakulam in Tamil Nadu. Prior to his entry into politics, he owned agricultural lands and a tea shop which he still owns.
In 1996, he was the chairman of Periakulam municipality in 1996.
He contested legislative assembly election for the first time in 2001 from Periakulam constituency and become the PWD Minister.
In September 2001, he was unanimously elected Chief Minister of Tamil Nadu by the AIADMK after the Supreme Court quashed the then CM Jayalalithaa's appointment. The party argued that the appointment was done because of his loyalty to Jayalalithaa and not due to seniority.
During his stint as Chief Minister between September 2001 to March 2002, he faced severe criticism from several quarters for heading a ‘puppet government closely micro-managed by Jayalalithaa'. Paneerselvam not only refused to sit on the Chief Minister's chair but was reluctant to sign files.
In March 2002, he resigned as Chief Minister after Jayalalithaa's conviction was overturned. After resignation he became the Public Works Department minister in the Jayalalithaa government.
In 2011 Assembly polls, he contested from Periyakulam assembly constituency and was given Finance portfolio in Jayalalithaa's Cabinet. This year, the AIADMK chief gave him additional charge of public works department.
He was the leader of the AIADMK legislative party and the Leader of the Opposition in the Tamil Nadu Legislative Assembly for about two weeks, after the party lost the assembly polls in 2006.
He has been twice elected to the Tamil Nadu Assembly from Periyakulam constituency.