Seymour was born the son of former slaves in Centerville, in the U.S. state of Louisiana. As a grown man he became a student at a newly formed bible school founded by Charles Parham in Houston, Texas, in 1905. It was here that he learned the major tenets of the Holiness Movement. He developed a belief in glossolalia ("speaking in tongues") as a confirmation of the gifts of the Holy Spirit. He later moved to Los Angeles to minister in churches. As a consequence of his newfound Pentecostal doctrine he was removed from the parish where he had been appointed. Looking for a place to continue his work, he found a run-down building in downtown Los Angeles located on Azusa Street.
From his base on Azusa Street he began to preach his doctrinal beliefs. Seymour not only rejected the existing racial barriers in favor of "unity in Christ", he also rejected the then almost-universal barriers to women in any form of church leadership. This revival meeting extended from 1906 until 1909, and became known as the Azusa Street Revival. It became the subject of intense investigation by more mainstream Protestants. Some left feeling that Seymour's views were heresy, while others accepted his teachings and returned to their own congregations to expound them. The resulting movement became widely known as "Pentecostalism", likening it to the manifestations of the Holy Spirit recorded as occurring in the first two chapters of Acts as occurring from the day of the Feast of Pentecost onwards. It is believed, Charles Harrison Mason, founder of the Church of God in Christ, received the Holy Spirit at the revival.
Most of the current charismatic groups can claim some lineage linking them to the Azusa Street Revival and William Seymour. While the movement was largely to fracture along racial lines within a decade, the splits were in some ways perhaps less deep than the vast divide that seems often to separate many whitereligious denominations from their black counterparts. Probably the deepest split in the Pentecostal movement today is not racial, but rather between Trinitarian and Onenesstheologies.
While there had been similar religious movements in the past (the Cane Ridge, Kentucky, religious movement a century before in the Second Great Awakening being one such example), the current worldwide Pentecostal and charismatic movements are generally agreed to have been in part outgrowths of Seymour's ministry and the Azusa Street Revival.