The main catalyst for the American Civil Rights Movement in the 1950s and 1960s was the systematic racial discrimination and segregation faced by African Americans in the United States. Key events, such as the 1954 Supreme Court decision in Brown v. Board of Education, which deemed segregation in public schools unconstitutional, sparked activism. The movement gained momentum through organized protests, legal challenges, and influential leaders like Martin Luther King Jr. and Rosa Parks. Grassroots initiatives aimed to end racial injustices, desegregate public facilities, and secure voting rights, profoundly impacting American society.