His father, Johann Georg Schmucker, was a German immigrant and an ordained pastor in the Pennsylvania Ministerium.

After teaching briefly at the York Academy, Schmucker went on a missionary journey to the western frontier of Kentucky and Ohio.

[6] Because Schmucker denied the Real Presence in the Lord's Supper, he is categorically placed in the "Un-Lutheran" camp by Charles Porterfield Krauth.

Schmucker wrote, "worthy communicants, in this ordinance, by faith spiritually feed on the body and blood of the Redeemer, thus holding communion or fellowship with Him.

"[7] This demonstrates Schmucker held to the Calvinist spiritual explanation of the Lord's Supper rather than the Lutheran teaching of Sacramental Union.

[8] Wilhelm Sihler of the Missouri Synod criticized Samuel Simon Schmucker, terming him "apostate," and asserting that Schmucker and other like-minded leaders of the General Synod were "open counterfeiters, Calvinists, Methodists, and Unionists...traitors and destroyers of the Lutheran Church".

[9] The Schaff-Herzog Encyclopedia of Religious Knowledge states his theological position was a mix of "Puritanism, Pietism, and shallow Rationalism" rather than Lutheranism.