Lyndon B. Johnson played a pivotal role in advancing Civil Rights legislation in the United States during his presidency. Johnson signed the Civil Rights Act of 1964 into law, which prohibited discrimination based on race, color, religion, sex, or national origin. This legislation was a landmark achievement in the Civil Rights Movement and was a major victory for African Americans in their fight for equality.

Johnson also signed the Voting Rights Act of 1965, which aimed to overcome legal barriers at the state and local levels that prevented African Americans from exercising their right to vote. This legislation was instrumental in increasing African American participation in the political process and securing their voting rights.

Overall, President Lyndon B. Johnson's support for and signing of key Civil Rights legislation marked a significant shift in U.S. policy and helped to advance the cause of racial equality in America.