Thurgood Marshall: America’s First African American Supreme Court JusticeThe great grandson of a slave, Thurgood Marshall was born in Baltimore, Maryland, on July 2, 1908. At the age of 25, Marshall graduated first in his class from Howard Law and joined the National Association for the Advancement of Colored People (NAACP), the nation's largest and oldest civil rights organization. As NAACP counsel, Marshall used the constitution to successfully argue for a slew of rights now taken for granted, and forced the University of Maryland Law School to admit its first black student, just five years after that same school had rejected Marshall due to his race.