ICS was born in the 1960's when local Reformed Christians banded together to form the Society for Christian Education in Southern Alberta. Their first goal was to create a Christian Grade School. A building from the Claresholm Air Force Training Base was the first home of Immanuel Christian School when it was moved to 802-6 Avenue North. Classes started on September 4, 1962, with 63 students enrolled from Grades 1-6 and three teachers. Over the next three years grades 7-9 were added, with the first grade 9 class graduating in June 1966.
In the spring of 1971 kindergarten was started. It later was extended and modified to meet government regulations under the Early Childhood Services Program. Immanuel's kindergarten program was accepted in 1973 and has been in operation ever since. In 1974 plans to extend our school to include a Senior High started. Then in 1975, with definite plans for a Senior High wing, the Society approved the concept of a Christian High School and in September 1976 it started. During that term, two classes of grade ten began in that wing. Two grade 11 classes were added in 1977 and a grade 12 class in 1978. The first grade 12 class graduated on June 14, 1979.
In 1977, the largest addition to Immanuel was undertaken. A regulation size gym, a typing room, a band room, a printing room, a library, and six classes were added. Also, two classes were renovated to be used as a lab and an art room. Since then many upgrades to classrooms, the staff room, computer room, science lab, counseling room, shop and music room have been completed. The Society also built and opened a campus in Taber during the 1980's.
In 1996 the Society purchased the old George McKillop School on 5th Ave N to replace the Elementary "H" wing. Six new classrooms were built on the new campus and the ICS elementary classes were moved there in the fall of 1997. Now Immanuel Christian Elementary is located on their own campus (K-6) with Immanuel Christian Secondary School remaining at the 6th Ave N location.
Most of the "H" wing was torn down the following year turning it into an "I" wing. In 2000, a fire destroyed the remaining rooms of the "I" wing creating a real need for storage space. This need, along with increased enrollment demands, led the Society to vote (in the fall of 2000) for the construction of a new library, computer room, music room and classrooms at the ICHS campus. Construction on what was to be called the "LIFE Wing" started in the summer of 2002. In 2004 (after two years of construction and school occurring at the same time) the LIFE Wing was completed.
In 2009, the School Society approved the Taber local's request to separate the Taber Campus from the Society and enter an Alternate School arrangement with the Horizon School District. As of September 2009, the Taber campus has been operating as Taber Christian School as a fully-funded alternate program under the Horizon School District.
In 2015, the Society passed a motion to sign an agreement with Lethbridge School Division to become an Alternate Christian School Program. Since September 2015, Immanuel Christian Schools have been operating as a fully funded alternate program under Lethbridge School Division.
In 2016, the Grade 6 classrooms were transitioned from the elementary campus to the high school campus. A middle school (grades 6-8) philosophy and structure was adopted that aligned well with the established Lethbridge School Division school configurations. It was decided at that time to change the name of the high school campus to Immanuel Christian Secondary School to encompass the middle and high schools.