NEW DELHI — Muthuvel Karunanidhi, who parlayed his vocation as a prolific writer of films about the downtrodden into a political career that challenged the upper caste’s hold on Indian politics, died on Aug. 7 in Chennai, India. He was 94.

Doctors at Kauvery Hospital, where he died, said Mr. Karunanidhi suffered multiple organ failure after being admitted in late July.

India’s longest-serving legislator, Mr. Karunanidhi was elected to the state of Tamil Nadu’s assembly 13 times, serving from 1957 until his death. He was also the state’s chief minister five times — for a total of 19 years — starting in 1969.

Although his political career was concentrated in Tamil Nadu, Indian’s southernmost state, his influence was felt nationwide.