She defeated A Kingsly Solomon in the poll held to elect officer-bearers to the official employees union of The Hindu daily headquartered here.
Out of the total eligible 735 voters, 722 votes were cast including 12 postal votes and 13 abstained, sources in the union and DMK told PTI.
According to DMK sources, Kanimozhi is the first woman chief of The Hindu union. She had worked in the newspaper's editorial between 1996 and 2000, they said.
Former Union Minister and DMK leader N V N Somu was also a past president of the Union.
Also, a former DMK MLA, N P Ramajayam, was a past general secretary of the union.
For the post of general secreatry, veteran unionist M Kamalanathan was re-elected for the fourth time in a row defeating G Kumar.