O. Panneerselvam: the career, year by year
- 2001
- 2006
- 2011
- 2016
- 2021
- 2026
Elected to the Assembly 6 times: Periyakulam, Bodinayakanur
- Assembly win
- Office held
- Party
- Chief Minister
- 1996
First elected Chairman of the Periyakulam municipality on the AIADMK ticket; emerges as a Jayalalithaa loyalist.
- 2001
First MLA win from Periyakulam constituency on the AIADMK ticket.
- 21 Sep 2001 – 2 Mar 2002
Sworn in as Chief Minister of Tamil Nadu for the first time (162 days), after Jayalalithaa was barred from contesting following her conviction in a corruption case.
- 2006
Re-elected from Periyakulam on the AIADMK ticket — 68,345 votes, a 14,834-vote margin over the DMK's L. Mookaiah.
- 2011
Wins from Bodinayakanur (post-delimitation) on the AIADMK ticket; sworn in as Finance Minister in Jayalalithaa's third cabinet.
- 28 Sep 2014 – 23 May 2015
Sworn in as Chief Minister for a second term (237 days) after Jayalalithaa was again disqualified pending appeal.
- 6 Dec 2016 – 15 Feb 2017
Sworn in as Chief Minister for a third term (72 days) after Jayalalithaa's death; resigned during the V. K. Sasikala power struggle, claiming he was 'compelled to resign'.
- Aug 2017
OPS and EPS factions merge; OPS becomes Deputy Chief Minister of Tamil Nadu, a post he held until May 2021.
- 11 Jul 2022
Expelled from AIADMK for 'anti-party activity' after losing the leadership war to Edappadi K. Palaniswami; the general council abolished the dual-leadership structure. Court challenges followed and were ultimately dismissed.
- 27 Feb 2026
Joins the DMK in the presence of CM M. K. Stalin and Deputy CM Udhayanidhi Stalin at DMK headquarters in Chennai; resigns his Bodinayakanur Assembly seat the same day to recontest as a DMK candidate.
- 4 May 2026
Won Bodinayakanur for the DMK (polling was on 23 April).
See the full 2026 result - 11 May 2026
Took oath as MLA in the 17th Tamil Nadu Legislative Assembly — his sixth Assembly term overall.