The prominent political leader who advocated for civil rights using passive resistance was Martin Luther King Jr.. His philosophy was deeply rooted in the nonviolent teachings of Gandhi and focused on achieving social justice through peaceful protests and civil disobedience. King played a pivotal role in the American civil rights movement of the 1950s and 1960s, leading significant events like the Montgomery Bus Boycott and the March on Washington, where he delivered his famous "I Have a Dream" speech.