Before the Second Vatican Council, the efficacy of dialogue between Catholics and non-Catholics was often disputable. Nevertheless, the practical reality of American religious pluralism necessitated Catholic engagement with non-Catholics around pressing social issues. This reality was especially evident in the Civil Rights Movement, during which pro-equality Catholics considered how to politically effectuate the legal recognition of racial equality. Through a case study of former Boston College Law School Dean William J. Kenealy, this article proposes that pro-equality Catholics turned to the Natural Law as a foundation for interreligious social advocacy during the Civil Rights Movement. After exploring Kenealy’s formative intellectual influences, this article identifies the philosophical and historical features of the Natural Law that made it appear particularly ripe for promoting interreligious consensus around racial equality. In concluding, this article suggests that the resonances between Kenealy’s work and the National Catholic Welfare Conference’s 1958 pastoral letter on racial equality reflect the Natural Law’s prominent role in American Catholic thinking about civil rights at mid-century.