His Grace Bishop Ioan Casian was born on February 20, 1969, in the city of Comăneşti, Bacău country. His parents were Priest Ioan and Preoteasa Mariana.

He attended elementary school in his native city from 1975-1983, then went on to the Industrial High School, Math and Physics section from 1983-1987. From 1989-1993 he was a student at Andrei Şaguna Theological Faculty in Sibiu, and graduated with a thesis in Canon Law on the subject, „Iconomia in the Orthodox Church”, under the guidance of Dr. Ioan Floca. During his student years he also came into contact with the spiritual and theological renewal movement then represented by His Grace, Vicar Bishop Serafim Joantă.

From 1993-1995 he stayed at St. John the Baptist Monastery in Jerusalem, where he received the first elements of a monastic formation. At the same time he took courses in ancient Greek at the Flagelazione Pontifical Institute, and in French at the French Culture and Language Institute there, as well as beginning courses in iconography and icon restoration. In 1995 he was tonsured a rasophore by Metropolitan Serafim of Germany and Northern Europe.

From 1995-1998, through an scholarship for excellence received from a group of 20 Catholic monasteries, he studied at the Pontifical Athenaeum of Saint Anselm (Rome), at the Faculty of History, Monastic Spiritualty, and Patristics, as well as studying History, Art, and Classical Languages at the Pontifical Oriental Institute, graduating with a thesis called “The Path to Freedom: a study of St. Maximos the Confessor’s Commentary on the Lord’s Prayer”, having as his academic coordinators Jeremy Driscoll and Maciej Bielawski. During the same period he did internships in several European monasteries: Exaltation of the Holy Cross Benedictine Monastery (Chevetogne, Belgium), St. Dominic of Silos Benedictine Monastery (Burgos, Spain), and the Monastic Community of Bose, Italy. He attended the Romanian St. John Casian Parish in Rome, assisting with the chanting.

Following his studies, he was called by Metropolitan Iosif of Western Europe to come to Paris, where he served as administrative secretary until 2002. During the same period he directed the choir of St. Paraschiva–St. Genevieve Church (Paris), conducting several concerts in Amiens, Paris (Notre Dame Cathedral, St. Etienne Greek Orthodox Cathedral), UNESCO, Neuilly. He was also translator and editor of the metropolitan magazine Sfântul Ioan Casian.

On June 23, 2001, he was ordained deacon, and on the next day priest, assigned to the Exaltation of the Holy Cross Monastery in Malvialle, France. On November 1, 2001, he was tonsured with the Little Schema, under the same monastery. He did a short internship at St. John the Baptist Monastery (Maldon, Essex, England). From 2002-2003 he was priest of St. Joseph of Bordeaux parish, where he held several conferences on the subject, The Great Feasts of the Church Year in the Orthodox Church in collaboration with the Ogivky Christian Art and Iconography Association, and a Biblical workshop on several biblical texts.

From April 2003 until June 2006 he was the priest of St. Nicholas Romanian Orthodox Church in Queens, New York (USA), where he also edicted the parish newsletter. He held a series of conferences and catechetical lectures on themes inspired by the Gospel Readings of Great Lent (Fasting and its Meaning, Orthodoxy, Prayer, On the Holy Cross, Stages in the Spiritual Life). He was in charge of the St. Dumitru Retreat and Monastic Center (Middletown, New York),where he set up a memorial room in honor of its founder, Archimandrite Vasile Vasilachi. He also led a Christian summer camp there for children from metropolitan New York City, the Eastern US, and Canada in 2004-2007. In 2004 he received the title of Archimandrite.

Having been proposed by Archbishop Nicolae and approved by the Eparchial Council, Archimandrite Ioan Casian was elected on March 2, 2006 by the Holy Synod of the Romanian Orthodox Church as Vicar Bishop for the Romanian Orthodox Archdiocese in the Americas. On July 2, 2006, he was ordained to the episcopate at Sts. Constantine and Helen Cathedral in Chicago. Since then he has conducted his pastoral mission especially among the Romanian parishes on the East Coast of the U.S. and Canada. He initiated the construction of the new church at the St. Dumitru Retreat and Monastic Center in Middletown, NY, as well as the iconography project of the St. Nicholas parish in Queens, NY. He has given several lectures—at the parish of St. John the Merciful (Toronto, September 2007), two lectures inspired by the thinking of St. Silouan – “St. Silouan the Athonite in Orthodox Christian Thought” and “St. Silouan—Askesis of the Broken Heart”; at Columbia University’s Union Theological Seminary (New York) a lecture entitled, „The Historian’s Mission in the Church”; and on the occasion of the symposium on the theme of „Transfiguration” (December 2007) the lecture, “St. John Chrysostom’s Homily on the Transfiguration. A structural analysis, meaning, and importance”.