Originally known as the German Reformed Church, the RCUS was organized in 1725 thanks largely to the efforts of John Philip Boehm, who immigrated in 1720.

During the 19th century the German Reformed Church debated issues such as revivalism and especially the Mercersburg Theology of John Nevin and Philip Schaff.

More conservative clergy and members united to form the Eureka Classis of the RCUS, in order to continue classical Reformed worship and polity.

The classis objected to the ESNA's admixture of Lutheran teachings with Reformed practices; most of its churches and members had descended from late 19th-century immigration either from parts of Germany where Reformed confessionalism had taken hold,[2] or from the Volga River region of Russia, where ethnic Germans had been isolated from liberalizing influences in the motherland.

By contrast, most RCUS churches, classes, and synods located in the eastern United States had significantly assimilated into generalized or what became known as mainline American Protestantism, and become more ecumenical.

The RCUS believes in Biblical inerrancy, including a teaching that Genesis 1:1—2:4 must be understood as a literal 24-hour, six-day creation account.

The RCUS also does not allow women to hold special office (elders, deacons, pastor), a stance held by many conservative Reformed or Presbyterian bodies in the United States.

In addition, the RCUS rejects some standard positions associated with American fundamentalism such as premillennialism and total abstinence from alcoholic beverages, holding instead a focus on a European Calvinist orthodoxy rather than American-style revivalism.