The influential civil rights leader known for his philosophy of peaceful protest was Martin Luther King Jr. He was a central figure in the American civil rights movement during the 1950s and 1960s, advocating for nonviolent resistance against racial segregation and discrimination. Inspired by Mahatma Gandhi's principles, King organized peaceful protests, demonstrations, and marches, including the historic March on Washington in 1963, where he delivered his famous "I Have a Dream" speech. King's efforts were instrumental in the passage of key civil rights legislation, including the Civil Rights Act of 1964 and the Voting Rights Act of 1965, profoundly impacting American society.