In 1903, the founding pastor, Father Israel McGovern, accepted the challenge of building a parish. As the numbers grew, the challenge grew. Father McGovern shepherded Assumption parish through enormous growth - from 75 parishioners in 1903 to 897 families at the time of his death in 1934. He did not have an assistant until 1922. During his time as pastor, Father McGovern supervised a number of land purchases and building projects, including a rectory, two churches, two schools, and a convent. Along with these necessary improvements came the worry of sinking into debt during uncertain financial times. From the annals of the parish, we learn, "Father McGovern, now in his 64th year, with his pioneering days behind, was bending lower and lower under the weight of his new responsibilities and his added years" (50th Anniversary Book, 1953).

In late 1909, two Sisters of St. Joseph from Baden, Pennsylvania, were assigned to teach the parish children until a formal school could be instituted. A house on Jackson Avenue, next to the church, was purchased and became the first convent. By September of 1913, when Assumption School was officially opened, there were 120 students in grades one through six. The following Sisters of St. Joseph arrived to teach the children: Sisters Blandina Maxwell, Marian Klunk, Mary Alice Fisher, Geraldine Conrad, and Henrietta Wolfhope. Their classrooms were separated by only a black curtain - no doors! The school grew tremendously, with nearly 500 students by the early 1920s. In 1931, when the new church was dedicated, the old church was converted into the school building.

The beloved pastor died on November 14, 1934. The Pittsburgh Post-Gazette carried the following item: "A tribute to Father I. J. McGovern, founder and for 31 years, Pastor, of the Catholic Church of the Assumption, was paid by stores of Bellevue and officials and clergy of surrounding boroughs yesterday morning. Solemn Requiem High Mass yesterday at 10 o'clock for Father McGovern, who died Friday in St. John's Hospital, was attended in a body by Protestant ministers of Bellevue and Avalon. Officials of the two boroughs and Ross Township attended, and as the cortege moved through the streets in a driving rain, business was suspended."

Father McGovern's vision, dedication, wisdom, and great courage gave Assumption the strong beginning it needed to move into the future.