Jagannathan was born to Devakiyamma in Changanassery, Kerala, India in 1938. He did his primary education from Thuravoor L.P School, Vaikom Government School. He got training from Rashtriya Anushasan Yojan at Rajasthan and won first rank in it.
He worked as Instructor at L.D.S Training Institute, Indore, Madhya Pradesh for four years. He also worked as Physical Education Officer at Neyattinkara Government High School, St. Joseph’s High School, Thiruvananthapuram, Poojappura Government High School and at Javahar Bal Bhavan, Thiruvananthapuram. He held posts as Government Welfare officer and Govenernment Sports Director Administrator.
He was an active member of the Malayalam theatre scene along with G. Aravindan and Nedumudi Venu. He played the noted character of Aattappandaram in the play Avanavan Kadamba written by Kavalam Narayana Panicker and directed by Aravindan.Jagannathan also directed four plays: Pathanam, Parivarthanam, Karadi and Vivahalochana.
Jagannathan’s film debut was in Oridathu (1986), directed by Aravindan.[ He acted in over 100 Malayalam films. Ardhanaari (2012) was his last film to be released before his death. Jagannathan also played roles in many television serials, including Kairalivilasam Lodge, which made him popular among Malayali households.
Jagannathan died on 8 December 2012 at Poojappura in Thiruvananthapuram, Kerala.