Martin Luther King Jr. was a prominent leader in the American civil rights movement during the 1950s and 1960s. He is best known for advocating nonviolent resistance to combat racial segregation and discrimination, inspired by the teachings of Mahatma Gandhi. His famous speech, "I Have a Dream," delivered during the 1963 March on Washington, called for equality and justice for all people, regardless of race. King's efforts led to significant legislative changes, including the Civil Rights Act of 1964 and the Voting Rights Act of 1965. He received the Nobel Peace Prize in 1964 for his commitment to achieving social change through peaceful means. His legacy continues to inspire movements for justice and equality worldwide.