F. F. Bosworth was among the preeminent Pentecostal ministers of the early 1900s. He participated in the 1906 Azusa Street Revivals that began the Pentecostal movement. His teachings largely aligned with Charles Parham, but he did not teach tongues as the evidence of the holy spirit. He held several large healing campaigns through the 1920s with his brother B. B. Bosworth. He was one of the founding leaders of the Assemblies of God.
He joined the Branham campaigning team in 1948 and was a regular minister in the campaigns in the years leading up to his death in 1958. His sermons tended to focus on the doctrine of divine healing, and it was during his debate on that topic with with a baptist minister in Houston, Texas, that the iconic photo of Bro. Branham was taken with the glaring light over his head.