The National Bar Association was established in 1925 as the "Negro Bar Association" after Gertrude Rush, George H. Woodson, S. Joe Brown, James B. Morris, and Charles P. Howard, Sr., were denied membership in the American Bar Association. The young Charles Hamilton Houston, future dean of Howard University Law School, also helped with the founding.

Its first president was George H. Woodson of Des Moines, Iowa. Arnette Hubbard became the NBA's first female president in 1981.

In 1940, the NBA attempted to establish "free legal clinics in all cities with a colored population of 5,000 or more." Its members supported litigation that achieved a US Supreme Court ruling that defendants had to be provided with legal counsel.

In 2010, the NBA partnered with the U.S. Census Bureau to work toward a complete and accurate count of the nation's population through various outreach activities