Necessary amendments were made in rules facilitating 63-year-old Stalin's elevation to the post at the DMK general council meeting where Karunanidhi was not present.
Alongside his present post of Treasurer, Stalin will now be holding the position of working president, party veteran and general secretary K Anabazhagan told the meet while seconding the resolution naming Stalin as party working chief.
This is the first time in the history of the over 60-year-old DMK that such a post has been created.
The working president will have the powers of the president, Anbazhagan added.
Though in hierarchy, the president continues to be the top post, the working president's post is seen as the numero uno position now given the failing health of Karunanidhi who was recently hospitalised twice for illness.
Party organisation secretary and Rajya Sabha MP, R S Barathy, moved the resolution proposing Stalin's elevation as working president and it was also seconded by party principal secretary Durai Murugan.
In his brief acceptance address, Stalin broke down while referring to the failing health of his 92-year-old father and party president Karunanidhi.
He said while he felt very happy when he assumed several party positions in the past, he did not feel so now, in a reference to Karunanidhi's health.
Stalin said he viewed his elevation only as a responsibility and his role would be to aide the party president. He later called on Karunanidhi at the Gopalapuram residence and sought his blessings.
Duraimurugan, who was a minister during the DMK regime, hailed Stalin and said the party was ready to abide by him.
Soon after Stalin was named working president, celebrations broke out with cadres bursting crackers and distributing sweets.
Image: DMK leader M K Stalin. Photograph: Courtesy, M K Stalin's Facebook page.
When will M K Stalin, the chosen one, take over?
Stalin, all DMK MLAs thrown out of TN assembly
Stalin brings civility back into TN politics, but there's a hurdle
DMK's Karunanidhi makes Stalin political heir
Why Rahul did not meet Karunanidhi in TN