Martin Luther King Jr. was an American clergyman and civil rights leader who led the civil rights movement in the 1950s and 1960s. He helped organize the Montgomery bus boycott and advocated for non-violent civil disobedience. King led protests against racial discrimination and segregation, delivering his iconic "I Have a Dream" speech. He was awarded the Nobel Peace Prize in 1964 and continued his advocacy for equality and justice until his assassination in 1968.