He is the second son of the former Chief Minister of Tamil Nadu, M. Karunanidhi and his second wife Dayalu Ammal and the head of South Zone of Dravida Munnetra Kazagham (up to 2014).

Karunanidhi always appeared to prefer his younger son, M. K. Stalin, Chief Minister of Tamil Nadu[3] Alagiri shifted his base to Madurai during 1989 and did not hold any post officially in the party.

[4] Following the by-poll victories in the state, Alagiri was given the ticket for Madurai Lok Sabha Constituency in 2009 general elections, which he won eventually and later went on to become a cabinet minister.

The succession crisis came out to a peak when party members loyal to Alagiri attacked the Madurai office of Dinakaran and set it to fire, in which three staff were killed.

[7] Azhagiri's name is associated with various controversies including conspiring in the murder of the former DMK Minister, T. Kiruttinan on 20 May 2003, initiating a cash-for-vote in Tamil Nadu for the Thirumangalam by-elections, attacking the Madurai office of the newspaper Dinakaran,[9] and the Dhaya Cyber Tech Park land grab case.

Azhagiri is accused of instigating the attacks of popular Tamil newspaper Dinamalar in February 1997 when the daily published a criticism about him.

[11] Kiruttinan was hacked to death by unidentified men while he was out for a morning walk near his residence in KK Nagar, Madurai.

The case was transferred to Chittoor in Andhra Pradesh after the DMK came to power in the state in 2006, based on an order by Supreme Court of India.

[18] A day after the incident, Prime Minister Manmohan Singh and Sonia Gandhi came to Chennai for felicitating Karunanidhi for 50 years in legislative assembly.

[20] There were several attempts of reconciliation by the Marans, with two public meeting, once during Stalin's birthday in March 2008 and other during May when Karunanidhi was discharged from a Chennai hospital having been treated for neck and back pain.

[25] Subsequently, the Corporation of Madurai recovered 8 cents (0.08 acre) of land from Dhaya Cyber Tech Park on 26 February 2013, that were encroached.

The concrete wall, trees and lawn in the encroached land were demolished by the Corporation officials amidst tight security.

[26] Azhagiri was appointed as the Minister of Chemicals and Fertilizers in the Union Cabinet, following UPA victory in the 2009 Indian Parliamentary Elections.

[28] Following the irregularities quoted by Jena, there were allegations by certain section of media of a possible scam to an extent of ₹1,000 crores in the fertiliser ministry.

Baalu, the head of MPs from the DMK party, to tender resignation in the Prime minister's office and to hand over the letter of withdrawal to the President on 20 March 2013.