Born in Kerala in 1908, he studied at Maha Rajah’s College of Science, Trivandrum. He passed his B.A. with mathematics as the main subject in April 1929.
He taught in S.C. Seminary, Tiruvalla for 1½ years between April 1929 and September 1930. He completed his theological studies at United Theological College, Bangalore and passed in 1933. Between 1933 and 1935, he worked in the church as Youth League Secretary and also as the Assistant to the V. Rev. V.P. Mammen who was the financial advisor to the church.
In 1935, he came to Singapore where he taught in private schools, the last of which was Pitman’s college. During the Japanese occupation, he worked at Pulau Samboe oil installation under the Japanese Military in charge of the calibration of petrol in the tanks. In 1944, he married Mary Vergis, daughter of Mr and Mrs P.T. Vergis in Kuala Lumpur.
He was ordained as Kaseessa of the church in 1947 and was appointed Assistant Vicar of the Malayan church. He served in Kuala Lumpur till 1954. During part of this period, he was also in charge of parishes in the states of Selangor, Perak, Kedah, Penang and Province Wellesley and the east coast of Malaya. Later, he was in charge of parishes in Selangor, Malacca, Negeri Sembilan and the east coast. For 12 years he was Principal of St Thomas School and Vicar of Singapore Parish between 1956 and 1961. He became the Senior Vicar in 1965 and has been in that position ever since. [Ed: The book The Mar Thoma Church: A Malaysian Perspective in which this biography appeared was published in 1986. Rev Thomas passed away in 1996.]
He was a member of the Malayan Christian Council from its beginning in 1948 and continued to be a member of its successors – the Council of Churches, Malaysia and Singapore (CCMS) and, after the separation, the National Council of Churches, Singapore (NCCS). He held offices of Treasurer and Vice-President in CCMS and in NCCS, President, Vice-President, Treasurer and Hon. General Secretary. He is currently its President. He has been the Treasurer of ECLOF Singapore from 1965-1981 and chairman since 1982. Since retirement from active parish work in 1978, has continued to be the Chairman of Singapore St Thomas Secondary School Management Committee.
As Rev T.N. Koshy pioneered the setting up of parishes, the task of consolidating and uniting them fell on Thomas Achen. A tireless worker of God, Thomas Achen is well-loved by all, young and old. He is full of compassion and has time for all who seek his help and is generous to a fault. Even after retirement from active service, Achen continues to be fully involved in all matters of the Church. He is an enthusiastic participant in its activities and always approachable.
In an article in The Ecumenical News, a publication of the CCMS, Thomas Achen has been described as a priest who has made great contributions to the Christian Council during his stewardship. The article adds: “His strength is in his loveable nature. For the sake of unity and Christian witness, he has walked the second mile many a time. His Ministry, both in his own Church and in the CCMS, has been a success and blessing to all.”