Rather than designating a single denomination, modern American Pentecostalism generally refers to Christian traditions that emphasize supernatural signs or “gifts of the Holy Spirit”—embodied in healing, speaking in tongues and ecstatic possession, or other proofs of divine favor—over ritual and hierarchy While emotional fervor has often characterized ongoing reform in American Christianity (e.g. the Great Awakening and evangelical traditions), a revival in Los Angeles, CA’s Azusa Street Mission in 1906 is taken to mark the birth of modern Pentecostalism. Over subsequent decades, this stress on visible signs of personal salvation and emotional fervor spread among the disfranchised in cities and rural areas, although congregations frequently divided over interpretations of the authenticity of these very signs. While many Pentecostals became associated with the Assemblies of God, Church of God and the Pentecostal Holiness Church, splinter groups built around charismatic leaders were also a constant feature of twentieth-century Pentecostalism—and a focus of attack by outsiders and media. Films, in fact, have almost invariably concentrated on corrupted leaders and fraudulent miracles (Elmer Gantry, 1960; the autobiographical Marjoe, 1973; Leap of Faith, 1992).

Documentaries as well have shown a fascination with exotic concrete signs of the supernatural—especially snake-handling, a test of faith actually confined to a small minority within Pentecostalism.

Pentecostalism experienced its own revival after the Second World War, embodied in builders like Oral Roberts, whose preaching and healing funded a university communication complex. Both tent revivals and the emergent power of television spread this coat-and-tie Pentecostalism, although competition among leaders and intersections of religious and social agendas fragmented religious experience and organization, and led to a decline in the late 1950s, even as both Pentecostalism and Christian media continued to evolve. In the 1990s, the major Pentecostal denominations had American memberships of over 10 million. They have also been active in missionary work among new immigrants as well as global evangelization that has established strong visible Pentecostal communities in Latin America, Asia, Africa and Europe (especially the former Soviet Union).

As with earlier general revivals, the appeal of Pentecostalism has also influenced mainstream churches, where various forms of spiritual renewal have intersected, sometimes uneasily, with more traditional rituals and orders since the 1960s. While Catholic Charismatic Renewal, for example, revitalized liturgical music, responses and even sociability in many parishes and college chapels, emphasis on the authority of individual spiritual redemption could also cause conflict with the authority of priests and the traditions of the larger community. In many of these denominations, however, Pentecostal elements have been reintegrated into both ritual and community structures.