St. Augustine was famous as the "Nation's Oldest City", founded by the Spanish in 1565. It became the stage for a great drama leading up to the passage of the landmark Civil Rights Act of 1964. A local movement, led by Robert B. Hayling, a black dentist and Air Force veteran affiliated with the NAACP, had been picketing segregated local institutions since 1963. In the fall of 1964, Hayling and three companions were brutally beaten at a Ku Klux Klan rally.

Nightriders shot into black homes, and teenagers Audrey Nell Edwards, JoeAnn Anderson, Samuel White, and Willie Carl Singleton (who came to be known as "The St. Augustine Four") sat in at a local Woolworth's lunch counter, seeking to get served. They were arrested and convicted of trespassing, and sentenced to six months in jail and reform school. It took a special act of the governor and cabinet of Florida to release them after national protests by the Pittsburgh Courier, Jackie Robinson, and others.

In response to the repression, the St. Augustine movement practiced armed self-defense in addition to nonviolent direct action. In June 1963, Hayling publicly stated that "I and the others have armed. We will shoot first and answer questions later. We are not going to die like Medgar Evers." The comment made national headlines. When Klan nightriders terrorized black neighborhoods in St. Augustine, Hayling's NAACP members often drove them off with gunfire. In October 1963, a Klansman was killed.

In 1964, Hayling and other activists urged the Southern Christian Leadership Conference to come to St. Augustine. Four prominent Massachusetts women – Mary Parkman Peabody, Esther Burgess, Hester Campbell (all of whose husbands were Episcopal bishops), and Florence Rowe (whose husband was vice president of the John Hancock Insurance Company) – also came to lend their support. The arrest of Peabody, the 72-year-old mother of the governor of Massachusetts, for attempting to eat at the segregated Ponce de Leon Motor Lodge in an integrated group, made front-page news across the country and brought the movement in St. Augustine to the attention of the world.

Widely publicized activities continued in the ensuing months. When King was arrested, he sent a "Letter from the St. Augustine Jail" to a northern supporter, Rabbi Israel S. Dresner. A week later, in the largest mass arrest of rabbis in American history took place, while they were conducting a pray-in at the segregated Monson Motel. A well-known photograph taken in St. Augustine shows the manager of the Monson Motel pouring hydrochloric acid in the swimming pool while blacks and whites are swimming in it. As he did so he yelled that he was "cleaning the pool", a presumed reference to it now being, in his eyes, racially contaminated. The photograph was run on the front page of a Washington newspaper the day the Senate was to vote on passing the Civil Rights Act of 1964.