With the loan secured, the basement church, the rectory, as well as a new convent were all begun. The year of 1927 was momentous for St. Edward parish. On December 24, twelve Dominican sisters occupied their new convent, which remains a landmark of the parish to this day. There were eighteen private rooms, as well as an infirmary, recreation and music rooms, and a parlor. Not only was the new convent finished in 1927, but so was the new rectory. Both built in an Italian architectural style, they are constructed of brick with a flemish bond. A beautiful cloister joined the rectory to the church. The "Lower Church," which is the basement foundation of the present church, was also finished in 1927. All Sacraments were administered in the Lower Church until the Main (or "Upper") Church could be completed. 

By 1928, the school enrollment had grown to 600 children and the school's auditorium, which had been used as a church, was converted into much needed classrooms. The architect for all this grandeur was Joseph McCarthy, who also worked for His Eminence George Cardinal Mundelein. 

In spring 1931, Father Corbett, a Viatorian priest, was named pastor of St. Viator. St. Edward parish was then placed under the direction of the archdiocesan clergy for the first time. Appointed as the fourth pastor, Rev. John J. O'Hearn greeted his new assignment with great enthusiasm. His concern for the children and teaching sisters who gathered daily in the overcrowded parish school compelled him to plan for a new school building. At a cost of $113,000, the new, two-story school was completed in 1939. It provided thirteen large classrooms, a basement hall, offices for the Mother Superior, and a music room. The original brick school, built in 1909, was remodeled into a parish center. 

As soon as the new school was completed, Father O'Hearn dauntlessly moved ahead with plans to resume work on the church, work which had been begun in the 1920s. The stately brick edifice was completed at the corner of Sunnyside and Kostner and dedicated by Archbishop Samuel A. Stritch on October 20, 1940. After 41 years of rapid growth and near-constant construction activity, St. Edward's campus showcased most of the same beautiful brick buildings still seen and used today, and was finally equipped to serve the vibrant Catholic community of Mayfair.