Martin Luther King Jr. was the prominent leader of the Montgomery bus boycott, which was a pivotal event in the civil rights movement. The boycott was sparked by the arrest of Rosa Parks, an African American woman who refused to give up her seat on a public bus to a white man. King emerged as the spokesperson of the Montgomery Improvement Association (MIA), which organized and led the boycott for over a year. He played a crucial role in inspiring the African American community to unite against racial segregation and discrimination on public transportation. King's leadership, his eloquent speeches, and his commitment to nonviolent resistance made him a symbol of the civil rights movement and brought national and international attention to the cause of racial equality.