Mar Jacob Angadiath was appointed the first Bishop of the newly erected St. Thomas Syro-Malabar diocese of Chicago in 2001 and ordained on 11 July 2001. The appointment of Mar Jacob Angadiath was a historic moment in the history of the Syro-Malabar Church as it was the first time that a Syro-Malabar diocese was created outside India.

Mar Angadiath was the first pastor and founder of St. Thomas Syro-Malabar parish in Dallas , Texas . He served the commmunity there for 17 years and was then transferred to Chicago to minister to the Syro-Malabar community of Chicago.

Mar Angadiath was ordained a priest for the diocese of Palai, Kerala and was appointed the Vice-Rector of the Minor Seminary, Palai. He had also worked in Kerala in various capacities as Assistant Pastor and Pastor.  Along with his appointment as the Bishop of St. Thomas Syro-Malabar diocese of Chicago, he was also appointed the Permanent Apostolic Visitator to Canada.