 He began his 25-year affiliation with the National Association for the Advancement of Colored People (NAACP) in 1934 by representing the organization in the law school discrimination suit "Murray v. Pearson".In 1936, Marshall became part of the national staff of the NAACP.In "Murray v. Pearson", Marshall represented Donald Gaines Murray, a black Amherst College graduate with excellent credentials, who was denied admission to the University of Maryland Law School because of its segregation policy.