Following the American Civil War many states enacted laws that enforced segregation between the races. Some of these laws required separate rooms in restaurants for whites and for colored people with separate entrances for each room (sometimes even requiring separate restaurants altogether), separate schools for white and colored children, separate toilet facilities, separate drinking fountains, different rail cars for each race or sometimes different sections of a partitioned rail car.

In Alabama in the 1950s public transportation was segregated so that black patrons had to sit in the backs of the busses, while white passengers had a reserved section at the front - unless that section was full, then black riders were required to give up their seats for white riders. This is exactly what Rosa Parks refused to do on 1 December 1955 in Montgomery, Alabama. The white section of her bus was full when a white man boarded the bus. As she was seated in the front seat of the black section she was ordered to surrender her seat to the white man. When she refused the bus driver called for the police and Rosa was arrested.

Rosa Parks was well-known in Montgomery, in response to her arrest the Womens Political Council organized a boycott of the busses for 5 December 1955, the date of Rosa's trial. The boycott was largely a success with only a handful of blacks riding busses that day, but Rosa was found guilty of disorderly conduct and fined. That evening, relative newcomer to town and pastor of the local Holt Street Baptist Church Dr Martin Luther King called a meeting at the church to discuss further action. It was decided to continue the boycott of the busses. Also at the meeting the Montgomery Improvement Association was formed, and the members selected Dr King to lead the organisation.

As black passengers made up at least two thirds of its ridership, the bus company was forced to cut schedules and raise fares to compensate for lost revenue. This angered the white riders who retaliated against blacks with harassment and terrorism. Blacks waiting for a cab or a ride were arrested for loitering, blacks giving rides to others were arrested for picking up hitchhikers. Near the end of January 1956 Dr King's home was bombed, although his wife and daughter managed to escape harm.

The Montgomery Improvement Association filed suit in federal court on behalf of those discriminated against by bus segregation. The federal court ruled in favor of the Association in June 1956, but the decision was appealed to the US Supreme Court. In November the Supreme Court upheld the lower court's ruling, declaring that Montgomery's bus segregation laws were unconstitutional. On 20 December 1956 the court order was served to Montgomery officials, ending the boycott 381 days after it began. The following day Dr King and Reverend Glen Smiley, a white minister, shared the front seat of a public bus.