According to most historians, the majority of northern urban Catholics before Vatican II (1962–1965) were ensconced in their parish boundaries, viewing their existence through the lens of the parish and focusing the majority of their attention on matters within their particular geographic location. As African Americans moved north during the Great Migration (1910s–1960s) and the racial dynamics of cities changed, some black Catholics began to organize for what they called “interracial justice,” a term that reflected their belief that black equality would benefit African Americans and whites. This article argues that the parish boundaries paradigm for understanding Catholicism prior to the reforms of Vatican II fails to account for the efforts of black Catholics working for interracial justice. This article considers four ways black Catholic interracialists moved beyond their parish boundaries: (a) the national networks they cultivated with white priests; (b) the theological doctrine of the Mystical Body of Christ they used to support their work; (c) the local relationships they developed with non-Catholics; and (d) the connections they made with young white Catholics. By advancing this argument, this essay highlights the relationship between race and religion—both how the institutional Catholic church reinforced racial hierarchies and how black Catholics leveraged their faith to tear them down. Finally, this article reorients the history of Catholic interracialism by focusing on black laypeople and connects two bodies of literature that rarely comment on one another: that of Catholicism and the long civil rights movement.