Sidelined All India Anna Dravida Munnetra Kazhagam (AIADMK) leader TTV Dhinakaran on Friday took oath as MLA from RK Nagar constituency.
Dhinakaran took at the Speaker's chamber as an Independent MLA.
He had on December 24 won the RK Nagar by-polls by a margin of 40,707 votes.
The key candidates in the fray besides Dhinakaran were AIADMK's E Madhusudhanan, DMK candidate N Maruthu Ganesh and BJP's Karu Nagarajan.
Dhinakaran got 89,013 votes, while Madhusudhanan secured 48,306 votes. Ganesh got 24,651 votes, while Nagarajan amassed 1417 votes.
The RK Nagar constituency went to polls on December 21, necessitated by the death of former Tamil Nadu chief minister J Jayalalithaa in December last year.