When Bishop P. J. Garrigan was named the first bishop of the Diocese of Sioux City, he soon divided St. Joseph's Parish for the convenience of the parishioners who lived in the south and east sections of Sioux City. While the buildings were being constructed, Mass and parish business took place in a private home across the street from the new church-school. Father J. F. Kerby, an associate at the Cathedral, became the first pastor of Immaculate Conception Parish.

In 1905, a small frame church and school combination building was completed on the corner of Rustin Avenue and Davis Avenue by 20 families who comprised the parish. The building still stands and has been converted into an apartment house. While this church was being used, Father Kerby rented a nearby house for a rectory.

New families moved in rapidly in Morningside and by 1909, there were 100 families in the parish. Father Thomas Coghlin served as administrator of the parish. A convent was built during Father Coghlin's pastorate for the Servite Sisters who served from 1912 to 1995.

In 1918, Father James J. Murphy was appointed pastor. It was during his administration that the present site of Morningside and Ridge Avenues was acquired for a new facility. The parish had outgrown its original site and in 1922 the construction of the church-school building was completed at a cost of $58,646. Four sisters taught 140 students in the new school, which held grades 1-8.

        Father Edward Smith was appointed to IC in 1933. Construction of the new Immaculate Conception Church began in 1952. It was completed and dedicated on Dec. 8, 1953, the feast of the Immaculate Conception. The colonial-style church, designed by the Catholic University School of Architecture, was recognized for its simple beauty. The cost of construction was $300,000.

Msgr. Frank Brady became pastor in 1964. A new parish center was built at a cost of $500,000. In 1967, 275 members in south Morningside were incorporated into the Nativity Parish. Since this time, the two Morningside parishes have cooperated in Catholic school education.

Msgr. Thomas Donahue followed in 1986 continuing the great tradition of previous pastors supporting Catholic Schools.

In 1993, Father Paul-Louis Arts became pastor of Immaculate Conception Parish. During his pastorate, the church was renovated and the new $4 million education center was built, replacing the 1922 school building.

In cooperation with Nativity Parish, the grade school was reorganized in 1996 to Mater Dei School. Pre-school through fifth grade are at Immaculate Conception and the middle school is at Nativity Parish.

Fr. Steve Brodersen followed in 2002. He was known for his enhancement of liturgies at Immaculate Conception.

In 2005, Fr. Dan Guenther came to IC. He is our current pastor and has been instrumental in community building and celebrating traditions. During this time, the parish celebrated its Centennial, established a Stewardship Committee, re-established the Parish Council and a Buildings and Grounds Committee.

The two Morningside parishes, together, share an associate pastor, a permanent deacon, a school, the baptismal preparation program, some sacramental programs and a Youth Ministry Program. The two parishes operate on a single calendar.