Yoohanon Mar Chrysostom (born 19 May 1944) is the Metropolitan Bishop of the Eparchy of Pathanamthitta of the Syro-Malankara Catholic Church. He was the third son of Abraham and Achiyamma of the Kalloor family at Kadammanitta, in Pathanamthitta District.
He completed his secondary education at Government High School, Kadammanitta. He joined St. Aloysius Seminary, Trivandrum. After the completion of his minor seminary formation, he was sent to Trichy to study philosophy and theology. He was ordained a priest by Benedict Mar Gregorios on 5 May 1973.
He started his pastoral ministry as the assistant vicar in the parishes around Balaramapuram. Later he has become the vicar of parishes of Venniyoor, Mulloor, Chowara and Vizhinjam. Then he was appointed as the director of St. Johns Leprosy and HIV Care Services at Pirappencode.
Then he was sent to do mission work in North America. When the Malankara Catholic Mission in North America was officially inaugurated he was appointed as the co-ordinator. In 1997 he was raised to the status of a Cor-episcopo.
Pope John Paul II appointed John Kalloor Cor-episcopo as the second bishop of the Eparchy of Marthandom on 16 April 1998. He was ordained a bishop with the name Yoohanon Mar Chrysostom by Archbishop Cyril Mar Baselios at Mar Ivanios Stadium, Trivandrum, on 29 June 1998. He was installed as the bishop of Marthandom on 1 July 1998 at Marthandom Cathedral.
Baselios Cleemis appointed Yoohanon Mar Chrysostom as the bishop of the newly created Eparchy of Pathanamthitta on 25 January 2010; he was enthroned on 20 March 2010.
Before being appointed a Bishop, John Kalloor served the Archdiocese of Washington for many years. Based at Holy Comforter-St. Cyprian parish in Washington, DC, he was a chaplain for DC General Hospital and coordinated ministry for Syro-Malankara rite Catholics in the United States.