St. Joseph was founded in 1845 in Sharpsburg. Little is known of the origins of the parish. It appears that, beginning in 1843, Sharpsburg was visited monthly from St. Philomena and Mass was celebrated in a private residence. Before that time, local residents had to travel to Pittsburgh or to Pine Creek to attend Mass. In 1845, the parish was established. Work on a small church building began in 1847 and was completed by the end of the year.
In that year, St. Joseph became a mission of St. Mary Assumption, Pine Creek, although the pastor of St. Mary decided to reside in Sharpsburg. Within two years, a larger brick church was built to replace the original building. The cornerstone of this second church was laid on June 25, 1848, and the completed church was dedicated on April 29, 1849.
The new parish consisted primarily of Irish and German Catholics, with the latter predominating. In 1852, the Germans formed their own congregation, St. Mary. Until St. Mary church was built in 1854, they continued to use St. Joseph Church for services. In 1863, St. Joseph was assigned a resident pastor.
As the population began growing, the church soon became overcrowded. In 1873, work began on a new church. The cornerstone was laid on May 4, 1873, and the church, though not completed, was dedicated on July 19, 1874. The church was renovated around 1900.
The church suffered major damage in the flood of March 17, 1936. For four months, Mass had to be celebrated in the school while the flood damage was being repaired. The church was again renovated in 1957, including the installation of new altars, confessionals and a baptismal font.
On February 29, 1960, a fire destroyed the nearby Madonna of Jerusalem church. St. Joseph Church was made available to Madonna of Jerusalem parish for Masses. This disaster brought to a head concerns about the declining population of Sharpsburg. The city had four churches situated near each other, with St. Joseph being the only territorial parish. The bishop determined that the Catholic community could best be served by relocating St. Joseph parish. On July 31, 1960, the bishop announced that the St. Joseph Church would be turned over to Madonna of Jerusalem parish and that a new St. Joseph Church would be built in O'Hara Township.
The first Mass in the new location was celebrated in a fire hall on August 7, 1960. A garage was converted into a temporary chapel and the first Mass was celebrated there on September 5, 1960. On December 10, 1960, ground was broken for a combined church/school building. The school opened on September 5, 1961 and the building was dedicated on October 31, 1961. The church was renovated in the mid 1980's.
After the turn of the 21st century, the congregation began to outgrow its church. On May 25, 2008, the parish broke ground for a new church. The completed building, which housed both the church and and a parish hall was dedicated on October 18, 2009.
With the turn of the century, trends in the Diocese of Pittsburgh began to reveal a decline in Mass attendance and sacramental participation. At the same time, the number of priests available for parish ministry also began to decline.
To address these challenges, Bishop David Zubik announced on April 12, 2015 a new diocesan initiative, On Mission for The Church Alive!, a consultative strategic planning process designed to foster viable, sustainable and vibrant parishes. As part of this process, the Bishop, in consultation with the faithful, began to consider new models of parish life based on pastoral needs, financial and temporal resources and available clergy.
In 2018, following the period of consultation, parishes were grouped together and served by a single clergy team to eventually form one new parish.
During this transition period, St. Joseph Parish remained an independent parish while sharing clergy and staff and eventually publishing a joint bulletin with the other parishes. This ended on July 1, 2021 when St. Joseph Parish merged with the parishes of St. Juan Diego, Sharpsburg; St. Pio Pietrelcina, Blawnox/Harmar and St. Scholastica, Aspinwall to form the new Christ the King Parish. As part of the merger St. Joseph Church remained open to serve the new parish.