Martin Luther King Jr. was the prominent civil rights leader known for his pivotal role in organizing the March on Washington for Jobs and Freedom on August 28, 1963. This monumental event drew over 250,000 participants and is most famous for King’s iconic "I Have a Dream" speech, where he articulated his vision for a racially integrated and harmonious America. King's advocacy for nonviolent protest and civil disobedience aimed to end racial segregation and discrimination against African Americans. His leadership and eloquent speeches were instrumental in advancing the civil rights movement, influencing legislation and societal attitudes regarding racial equality in the United States.