When the Belair estate of William Woodward was sold to the Levitt organization in 1960, the Belair section of Bowie began to develop so rapidly that Sacred Heart was unable to accommodate its parishioners. The Archdiocese of Washington immediately established the new parish of Saint Pius X in 1962. For the following three years. Sacred Heart was operated as a mission from that parish.

The continued rapid growth of the Belair development resulted in Sacred Heart Church being elevated to full status as a parish by Archbishop Patrick J. O'Boyle on May 30, 1965. Father John A. Lubey was appointed as the first Pastor. Almost immediately the requirements of the new parish exceeded the seating capacity of the Old Chapel structure. Seven Masses were being said on each Sunday, two of them at the Belair Theater. It was apparent that a new church had to be built to take care of the large number of parishioners. Plans were made in 1967 for a new church building that was to become the Main Church.

The new Church building located just off Route 450 at the foot of the hill below the Old Chapel was completed in the late summer of 1969. The first Mass was celebrated there on August 31,1969. Msgr. John F. Hogan, pastor of Sacred Heart Parish from 1972-2000 says, "We are indeed fortunate to have the two churches standing within sight of each other, one reminding us of our rich heritage and the other of our need to adapt as time goes on." The heritage of the Old Chapel transitions to the Main Church by using wood from the Original Priest's House built in c. 1741. Two of the beams form the cross for the crucifix in the center of the Main Church today. The rest of the wood was milled and fashioned into the Altar of Reposition (Chapel) at the Main Church, which houses the tabernacle. ''As we recall the events and difficulties of the early days of the Catholic Church in America," writes Msgr. Hogan in the Sacred Heart Church history book, "we are aware that these same difficulties exist today and that we must be constantly vigilant in protecting our heritage. For we know that the glory of this country is its religious heritage." Catholics are mindful, during this Jubilee year, not only of their faith but the blessing of religious liberty that is guaranteed by the First Amendment and which has been the strength of our national heritage over the years. How blessed is White Marsh in the illustriousness of its history!

The sculpture over the main entrance of the church is a triptych panel relief designed by Mr. Peter Brahms of Pittsburgh. In the center and main panel, the Hebrew word for Yahweh, the heart superimposed on a cross, and the dove symbolize the Trinity of the Father, Son, and Holy Spirit; the heart specially symbolic of the Sacred Heart as the parish patron. The outside panels illustrate the historical beginnings of the Catholic faith in Maryland and of this parish in Whitemarsh. The right panel depicts a ship, Indian tepees, and the state coat of arms, which symbolize the coming of the first Jesuit missionary (Rev. Andrew White) on the ships (the Ark and Dove) to minister to the colonists and the Indians in the colony of Maryland. The left panel shows the bishop's hat, a ballot box, and the episcopal coat of arms which symbolize the election at Whitemarsh of John Carroll as the first Catholic bishop in the United States. The episcopal coat of arms signifies the lions for the Carroll family, the Blessed Virgin as patron of America, and thirteen stars for the original colonies.