On the occasion, Karunanidhi, who was state chief minister five times, paid floral tributes at the memorials of DMK founder leader C N Annadurai and rationalist leader E V Ramasamy Periyar in Chennai.
Karunanidhi planted a sapling at his CIT colony residence and later a cake was cut in the presence of his family members, including his son and DMK Treasurer M K Stalin.
His daughter and Rajya Sabha MP Kanimozhi greeted him on the occassion. Party leaders like Duraimurugan and T R Baalu also went to his residence and wished him.
The DMK has announced a mega public meeting to be held at the YMCA grounds in Chennai later in the evening which will be addressed by Karunanidhi.
Karunanidhi, in his birthday message, urged party cadres to continue to work for the welfare of Tamil Nadu.
Recalling the "sacrifices" of his party for Tamil language, culture and the people, he said, "Let us work untiringly, I invite you with love."
Karunanidhi was Tamil Nadu chief minister five times between 1969-71, 1971-76, 1989-91, 1996-2001 and 2006-11.
Even though DMK lost the recent state assembly polls, it has emerged as a strong opposition, winning 89 seats.
Karunanidhi himself won from his native Tiruvarur, defeating AIADMK candidate R Pannerselvam by clocking the highest victory margin of 68,366 votes.
Party headquarters 'Anna Arivalayam' was decked up for the event and has been glittering with decorative lamps since Wednesday night.
DMK treasurer M K Stalin had appealed to party functionaries on Thursday to engage themselves in welfare activities like organising blood donation camps and planting saplings.
DMK district units celebrated his birthday by giving away sweets, welfare assistance like text and notebooks to school students and food and clothes to the poor.
Will it be Amma or Karunanidhi? Fates to be decided on Monday
After Lehman Brothers and StanChart, it's DMK time!
5 reasons why the DMK lost the plot in TN
Meanwhile in Chennai, both parties celebrate
DMK at crossroads, can Stalin take it forward?