Having expressed the desire to be a missionary priest in the United States, Fr. John was soon transferred and became the first permanent priest at St. Vladimir's Church in Chicago. This parish was later to become the [[Holy Trinity Orthodox Cathedral (Chicago, Illinois)|Holy Trinity Cathedral]]. As St. Vladimir's parish did not yet have their own building, his first major project was construction of the church building. Under the guidance of Bishop Tikhon, later [[Patriarch]] [[Tikhon of Moscow]] and saint, Fr. John enlisted the services of the noted architect Louis Sullivan to design the church. To finance the project, Fr. John sought and obtained donations from Tsar [[Nicholas II of Russia|Nicholas II]] as well as from a few Americans, notably Harold McCormick and Charles R. Crane who was the American ambassador to China. Construction of the church began in April 1902 and was completed the next year for the [[consecration of a church|consecration]] by Bishop Tikhon.

In the social side of parish life, he, with Fr. Alexis Toth, future St. [[Alexis of Wilkes-Barre]], was influential in the establishment of a major Orthodox mutual aid society that provided support for the many newly arrived immigrants. He also translated religious texts into English, looking to the time when church in America would consist of English-speaking members. Before his return to Russia, Fr. John helped to organize the first All-American Council that was held in Mayfield, Pennsylvania, in 1907.