Final answer:
Martin Luther King Jr. emerged as a leader of the Civil Rights Movement by leading actions like the Montgomery Bus Boycott, heading the SCLC, and delivering his "I Have a Dream" speech during the 1963 March on Washington.
Step-by-step explanation:
Martin Luther King Jr. emerged as a prominent leader of the Civil Rights Movement through various significant events and his involvement with influential organizations. King played key roles in civil rights actions such as the Montgomery Bus Boycott, which was sparked by Rosa Parks' arrest and the successful overturning of segregated bus laws. He also led the Southern Christian Leadership Conference (SCLC), which organized nonviolent protests across the South. The March on Washington for Jobs and Freedom in 1963 was another critical moment where King delivered his iconic "I Have a Dream" speech, further cementing his leadership role and the goals of the movement.