A year later he went to Philadelphia to continue his studies with Justus Henry Christian Helmuth and John Frederick Schmidt.
[2] In 1809, he was called to York, Pennsylvania, where he remained until failing health compelled him to retire in 1852.
He then moved to Williamsburg, Pennsylvania, where several of his children resided, and there he remained during the rest of his life.
[3] Schmucker was a founder of the 1821 General Synod of the Lutheran Church in the United States and was on the 3-person Pennsylvania Ministerium committee that planned the 1826 Lutheran Theological Seminary at Gettysburg (his son, Samuel Simon Schmucker, was elected the 1st professor).
For more than thirty years, he was one of the leaders of a Lutheran Church body in the United States, and actively engaged in all its important operations.