G. B. Cashwell first became a minister in the Methodist Episcopal Church, South, and later joined the Holiness Church of North Carolina in 1903. In November of 1906, he traveled to Los Angeles to visit the pentecostal revival at the Azusa Street mission. In early December, he had an emotional experience that he believed to be the baptism in the Holy Spirit and the evidence of speaking in tongues. Upon returning to Dunn, North Carolina, on December 31, 1906, Cashwell preached the pentecostal experience in the local Holiness church. Interest in the pentecostal experience was so great that he rented a local tobacco warehouse and began a month-long crusade. A revival broke out in North Carolina, especially in the holiness movement. Most of the ministers of the Pentecostal Holiness Church, the Fire-Baptized Holiness Church and the Holiness Free Will Baptist Churches were swept into Pentecostalism by this revival. Over the next six months, he toured the south preaching "Pentecost". His zeal and influence in spreading Pentecostalism through the south has earned him the title of the Apostle of Pentecost to the South.
In the summer of 1907, Cashwell brought the message of Pentecost to evangelists H. G. Rodgers and M. M. Pinson, who carried the message to Alabama, Florida, Georgia, and Mississippi. Later they would lead these churches into the Assemblies of God. Through Rodgers and Pinson, A. J. Tomlinson of the Church of God in Cleveland, Tennessee heard of Cashwell's message and invited him to Cleveland. On January 12, 1908, following a sermon by Cashwell, Tomlinson fell to the floor. He professed to receiving the baptism of the Holy Ghost and speaking in at least ten different languages.
In October of 1907, Cashwell started a publication in Atlanta, Georgia called The Bridegroom's Messenger. The periodical was created to spread the Pentecostal message over the country through a combination of sermons, articles, editorials, and testimonies. He edited it for a year before returning fully to his evangelistic efforts. The magazine was later taken over by Paul and Hattie Barth, who organized the International Pentecostal Assemblies (now International Pentecostal Church of Christ). It is still published by Beulah Heights Bible College in Atlanta, Georgia.
Although the influence of Cashwell was strong, his time of association with the Pentecostal movement was for a brief period of three years - from his "conversion" in 1906 until his departure from the Pentecostal Holiness Church in 1909. In 1910 and afterward, his name no longer appeared in the roster of ministers belonging to the Pentecostal Holiness Church. Cashwell distanced himself from "Pentecostalism", rejoined the Methodist church, and died from a heart-attack in 1916.
Cashwell's apostleship of Pentecostalism in the south influenced many denominations. About a dozen existing Pentecostal bodies can trace their Pentecostal heritage directly or at least in part to Gaston B. Cashwell, including: