[5][6][7] He served as a minister of Food, Revenue and Commercial Taxes in C. N. Annadurai's administration from 6 March 1967 to 10 February 1969.
In September 1970 he resigned from the cabinet, citing moral and ethical issues after charges of corruption, involving the purchase of a bungalow, were brought upon him by the opposition.
[11][12] M. G. Ramachandran was expelled from the DMK on 10 October 1972 and founded the party Anna Dravida Munnetra Kazhagam (AIADMK).
A rarity considering the fact that he was speaking the truth against his own party and by default jeopardising his own political future.
On 14 November, Mathiazhagan advised the then chief minister, M.Karunanidhi, to dissolve the house and face the electorate if the government was to earn its lost credibility.
Mathiazhagan and Ramachandran, the leader of the AIADMK in the assembly, filed a writ petition questioning the validity of the whole action .
He returned to DMK in 1974 and acted as deputy chairperson of planning commission of Tamil Nadu in the Kalaingar government.