During the late 19th and early 20th century, 13.5 million immigrants came to the United States, comprising almost 15% of the total population. The founders of the first Assumption Greek Orthodox Church in Chicago Heights were part of this wave of immigration. The founders were from various regions in Greece. But whether they came from Arcadia, Laconia, or Messenia on the mainland, or from islands such as Euvoia, Zakynthos, and Crete, they were united by their common religion, history, and culture. Within the larger society that they found themselves, they continued to identify themselves as Hellenes, strongly connected to the Greek Orthodox faith.

Dedicated on December 3, 1916, Assumption was the first Greek Orthodox church in the Chicagoland area to be located outside of the city limits. As the parishioners lovingly supported their church, Assumption was also said to be the only church without a mortgage during the Great Depression of the 1930's.

In the early 1960's, Parish Council President Dennis Cladis led the community in the search for a location to build a new church which would meet the needs of the parishioners. In July, 1969, Bishop Timotheos approved plans for a complex including a church, gymnasium, meeting room, and classrooms. With approximately $11,000 received from the James Pappas estate and $2,000 in savings, the community purchased land in Olympia Fields on Western Avenue, south of Joe Orr Road, for $27,000. The Assumption Church of Chicago Heights evolved into the Assumption Church of Olympia Fields, dedicated on October 3, 1976.