Pentecostal Church of God was started by Rev. Charles Jerls in the early 1950's in a store front building at 20th and Missouri Ave in Granite City, IL. It was then moved to a basement building on Charles Street before moving to 24th and Bromley Streets, where it was located when Rev. Harold Maynard became the pastor in August of 1959 (Sixth months later Mark Maynard was born.) The name of the church was changed to Pentecostal Assembly in 1962.

Pentecostal Assembly bought the current property on Maryville Road in 1964, developing the property, putting in Glory Lane and subdividing it. The church was built on the front portion of the property and found a new home at 4650 Maryville Road in August of 1965. Two years later the church became known as Calvary Pentecostal Assembly. Upon the purchase of a new bus in 1968, Calvary started their bus ministry.

In 1969, there was a real move of God and many were saved and added to the church. As a result, work began in June on the second sanctuary at the Maryville Road location, and was completed in December. The steeple was added the following year. Later, in 1974, Calvary Pentecostal Assembly started their children's church ministry under the leadership of Pastor Harold Maynard's daughter, Carol Maynard. Due to the continual increase in attendance over the years, a Sunday school wing was added to the church in 1983. The following year Harold Maynard's son, Mark, was added to the staff as Assistant Pastor.

In 1984, Calvary started Calvary Bible Institute which was in existence for 5 years. In 1990, the Rev. Harold Maynard reached 65 years of age and recommended that he and Mark trade positions. Mark Maynard was now Pastor Mark Maynard, and Rev. Harold Maynard became the Assistant Pastor.

Calvary purchased the two acre triangle lot to the north and added a parking lot in 1991, adding a two car garage the following year. In 1993, the 24 year old sanctuary was renovated. The platform was rebuilt and new carpet was installed. New pew cushions were also added. In August of 1994, Calvary made another change by adding Mark Goins to the staff as the youth pastor.

The church purchased more than 16 acres of land to the north in 1996. Calvary took the first of many mission trips to Mexico to build a roof for Brother Medesto's church in 1997. To this day, mission trips and mission giving continues to be of much importance to the people of Calvary. Pastor Mark started morning prayer in January of 1999, and it has continued to this day.

In 2001, the church name is changed to Calvary Life Church. The church started the first part of the planning process for a new sanctuary in 2004, with ground breaking in 2006. The new building was finally complete in late September of 2007 and included a new nursery, hospitality room, two bathrooms, a large office area, kitchen, prayer room, and a new sanctuary that holds up to 600 people. The first Sunday morning service was held on October 7, 2007.