St. Michael Church in Avella started as an outgrowth of the catechetical movement begun by Pope St. Pius X. In 1905, he established the Confraternity of Christian Doctrine in order to provide for the religious instruction of young Catholics. In 1907, Bishop Regis Canevin, the fifth bishop of the Diocese of Pittsburgh, instructed all pastors to institute the Confraternity of Christian Doctrine in their parish. Unfortunately, there were many parts of the Diocese that lacked a Catholic church, and therefore, lacked religious instruction. In Avella, many Catholics were attending the Presbyterian church because there was no Catholic church in the area. Miss Mary Dunn, a faithful laywoman, was inspired to begin catechetical work in areas that had not yet been organized into parishes. On January 24, 1909, a Sunday School, known as the "Sacred Heart Mission," was established in Avella with 17 students.

After the Sunday school was started, priests began visiting Avella monthly, under the direction of Fr. E. P. Griffin, for the celebration of Mass. Beginning on May 16, 1916, Fr. Clement Pfeifer, OFM Cap., was sent to Avella to say Mass regularly. From that time on, Mass was celebrated every Sunday and Holy Day. Through much prayer, sacrifice, fundraising, and pain-staking effort, a church was constructed in 1917, and named after St. Michael. In 1918, St. Michael became a parish, with Fr. William Merz being assigned its first resident pastor. Around 1920, a mission, St. Hermengild Chapel, was established at Penowa (near Meadowcraft Rock Shelter). The priests at St. Michael would celebrate Mass there once a month. In 1921 or 1922, land was purchased near the corner of Parker Road and Cross Creek Road for a parish cemetery. Various improvements were made to St. Michael church over the years, including the construction of a basement kitchen. In 1954, the misshion chapel of St. Hermengild was closed due to a dwindling population. In 1984, the former Avella Elementary School was purchased so that it could be used for youth faith formation (CCD).

In 1999, under the leadership of Fr. Pierre Sodini, and through the generosity of many parishioners who donated funds, supplies, and labor, a major renovation was initiated. To name just a few of the improvements:  a new vestibule (entrance) was built, an upstairs restroom was installed, an elevator was put in, the church kitchen was expanded and updated, and the parking lot was paved.

In 2012, Fr. Robert Staszewski was named administrator of St. Michael, and he was installed as pastor in 2014. He was also ministering as pastor of St. Ann in Bulger, where he was residing. This marked the first time in St. Michael's history as a parish that they shared a pastor with another parish. This became necessary due to the shortage of clergy. In 2014, there was an opportunity to address the need for additional parking. Because no one was residing in the rectory at St. Michael, the decision was made to tear it down so that the parking lot could be enlarged. St. Michael church celebrated its 100th anniversary in 1917.

In October of 2018, Fr. Staszewski retired. This coincided with the implementation of On Mission for the Church Alive!, the initative to better position the parishes in the Diocese to more effectively serve the spiritual needs of the faithful. The rest of that history can be found here. On July 1, 2020, St. Michael Parish merged with the parishes of St. Alphonsus, St. Ann, St. Columbkille, Our Lady of Lourdes, and St. Patrick to become St. Isidore the Farmer Parish, where the good work of spreading the Gospel continues to this day.