In the 1980s, Amirtham was Director on the Programme for Theological Education of the World Council of Churches, Geneva where he substantially contributed to Ecumenism and returned to India in the 1990s when he became Bishop - in - South Kerala until he stepped down from the bishopric in 1997 on attaining superannuation.
[6] While teaching at his alma mater, the United Theological College, Bangalore in the 1960s,[6] Amirtham qualified for undertaking research studies at the University of Hamburg, Hamburg, Germany enrolling for the Doctor of Theology programme specializing in Old Testament under Hans-Joachim Kraus[10] and Klaus Koch,[10] and was awarded the doctoral degree in 1969[10] based on his dissertation entitled The presence of God in the Psalms.
[10] In 1957, after ordination by South Kerala Diocese led by A. H. Legg, Amirtham began serving parishes within its ecclesiastical jurisdiction until 1963 when he was reassigned to take up the role of Spiritual formator.
[14] Spiritual formators teaching in affiliated institutions of the Senate of Serampore College (University) contributed essays honouring Amirtham beginning with the Tamil Nadu Theological Seminary, Madurai which published For the Sake of the Gospel in 1980[15] edited by Gnana Robinson, CSI followed by Board of Theological Education of the Senate of Serampore College under the leadership of K. C. Abraham proceeded to publish a contributory volume in 1993 titled New Horizons in Ecumenism: Essays in Honour of Bishop Samuel Amirtham.
[16] In 1988,[1] Amirtham was awarded a Doctor of Divinity degree by Honoris causa[1] during the tenure of D. S. Satyaranjan, IPC as Registrar of the Senate of Serampore College (University).