The prominent civil rights leader who delivered a powerful sermon on the steps of the Lincoln Memorial is Dr. Martin Luther King Jr.. His famous "I Have a Dream" speech, given during the 1963 March on Washington, called for an end to racism and for civil and economic rights. King’s eloquence and passion resonated with millions, inspiring a generation to engage in the civil rights movement. His advocacy for nonviolent protest and equality is a critical part of American history, making his legacy enduring and impactful in the fight for social justice.