K.M.Mathew was born on January 2, 1917 as the 8th among the nine children of K. C. Mammen Mappillai and Mammi (Kunjandamma) at Kuppappuram in Alappuzha district. After completing his schooling he joined CMS College Kottayam. Later, he completed his B.A Economics from Madras Christian College. He married Annamma Mathew on 7th September 1942 at his house in Kuppapuram.
Mathew started his career in 1940 as a planter in Chikmagalur where he joined his brother K.M.Jacob to take care of the family owned Bhadra Estate. He spent seven years in Chikmagalur estate. During this period, he opened a balloon manufacturing facility named Mysore Rubber Factory in the estate premises but the factory was soon closed due to the pollution it caused. The machinery at this factory was later transferred to Madras when his younger brother K. M. Mammen Mappillai started Madras Rubber Factory (MRF). In 1947, K M Mathew shifted to Bombay to start Allied Agencies.
After spending seven years in Bombay, K.M.Mathew moved to Kottayam and joined Malayala Manorama as the Managing Editor and General Manager on 15 May 1954. Following the death of his elder brother and the then Chief-Editor K.M.Cherian on 14 March 1973, K.M.Mathew took office as the Chief Editor of Malayala Manorama, a position he held until his death on 1 August 2010. K.M.Mathew infused professionalism into Malayala Manorama's management with the help of world's leading consultants. Under K.M.Mathew's leadership, Malayala Manorama grew into 17 editions and crossed a circulation of more than 1.6 million copies.
K.M.Mathew had served in the following capabilities:1.Chairman - Audit Bureau of Circulations(ABC) - (1970) Chairman - Press Trust of India - (1979), Chairman - Research Institute for Newspaper Development(RIND) - (1979), President - Indian Newspaper Society, Founder trustee - Press Institute of India, Member - Press Council of India, Executive Committee Member - Federation of International Newspaper Publishers and Editors, France.
In 1998, the nation honoured K.M.Mathew with Padma Bhushan. He has received many other awards including Foundation of Freedom of Information Award (1991), National Citizen’s award (1992), Ramakrishna Jay Dayal award (1995), Durga Prasad Chaudhary award (1996), Press Academy Award (1997) and B D Goenka Award (1996).On his first death anniversary, India Post issued a commemorative postage stamp. At the Parliament House, Prime Minister Dr Manmohan Singh received an album containing the stamp from Kapil Sibal, Union minister for communications and information technology.
His wife Annamma Mathew (1922–2003) was a culinary expert and Chief Editor of Vanitha. His book of memoirs, "Annamma", was published by Penguin in Malayalam (2004) and in English (2005).K.M.Mathew and Annamma Mathew have four children, Mammen Mathew, Philip Mathew, Jacob Mathew and Thankom Mammen. His autobiography titled "Ettamathe Mothiram" (The Eighth Ring) was published in 2008.
He died on August 1, 2010