Fr. Alummoottil Koshy Cherian was born and raised in an Orthodox Christian family. He received his Bachelor’s of Science degree in Mathematics from Kerala University and his B. Ed. from Brunnen College in Tellicherry, Kerala. He joined the Orthodox Theological Seminary, Kottayam, for the first batch of B.D.. course and successfully completed it in 1968. In between his studies, he was a teacher of Mathematics at the M.D. Seminary and M.G.M. High School in Thiruvalla. He earned his Masters in Education from Fordham University in New York, 1976.
As the church authorities knew him to be a disciplinarian, they appointed him Boarding Master of the boarding homes in M.D. Seminary and M.G.M High School, along with his teaching responsibilities. Meanwhile, he managed to remain active in church related activities such as the youth movement and Orthodox Christian Student Movement. Achen was elected the first general secretary of the high school wing of the student movement. He was also one of the founding members of the Bishop Pakenham Walsh Memorial Teaching and Healing Mission, the MGOCSM, and a supporter of the St. Paul’s Mission Training Center, Mavelikara under His Grace Dr. Geevarghese Mar Osthathios.