William Joseph Seymour was born in 1870 in Centerville, Louisiana, the son of formerly enslaved people. He came to Los Angeles in 1906 to preach at a small Holiness church on Santa Fe Street, was locked out of that church after a single service because his theology alarmed the pastor, and continued his meetings in a private home on Bonnie Brae Street. The initial group numbered around 50 to 60 people, a multiracial congregation unusual for the era. When the meetings at the Bonnie Brae house grew too large for the space, the group moved to the vacant building on Azusa Street. Attendance grew rapidly, often exceeding a thousand people at a time, gathered in a space that was never designed for that purpose.

The Azusa Street Revival was characterized by speaking in tongues — what practitioners called glossolalia, the spontaneous utterance of languages unknown to the speaker, understood in Pentecostal theology as a sign of baptism in the Holy Spirit. Services at the mission were highly improvisational: no set order of worship, no paid choir, no professional clergy running the proceedings in any conventional sense. Seymour preached from behind two wooden crates stacked together as a pulpit. The revival continued around the clock for extended periods, drawing participants from across the country who arrived, experienced the services, and then returned to their home communities carrying the theology and the practice with them.

In 1906 Los Angeles, and across the Jim Crow South, the kind of integrated worship that characterized the Azusa Street Mission was extraordinarily rare. White and Black worshippers prayed side by side, led by a Black minister in a city that maintained its own, less formal versions of racial separation. This interracial character was part of what made the revival notable to observers at the time, and it became significant to later scholars examining the revival's social dimensions. Seymour's theology held that the gifts of the Spirit — speaking in tongues, healing, prophecy — were available to all believers regardless of race or social standing. The practice reflected the belief.

Historians of religion generally credit the Azusa Street Revival as the primary catalyst for global Pentecostalism, now the fastest-growing branch of Christianity in the world. Participants who attended the Los Angeles meetings carried Pentecostal practice to every continent within a few years. Missionaries went to Africa, Latin America, and Asia; denominations formed that would become, by the 21st century, some of the largest Christian bodies in the world. The Assemblies of God, Church of God in Christ, and dozens of other Pentecostal and charismatic denominations trace their origins, directly or indirectly, to what began in that leaking building on Azusa Street. Seymour continued to lead the mission until approximately 1915, when the revival gradually wound down.