Garcia became legal counsel for the League of United Latin American Citizens, and the American GI Forum. He assisted in "Hernandez v. Texas" (1954), the first case by Mexican Americans to be heard by the U.S. Supreme Court. On January 19, 1953, he and attorney Carlos Cadena of San Antonio filed a writ of certiorari with the United States Supreme Court requesting review of the Hernandez case, because the trial was decided by an all-white jury in Edna, Texas. The legal expenses made it necessary for Carlos Cadena to make appeals on Mexican radio stations asking the community for donations. Due to this appeal, Chico Vasquez and Bill Aken (adopted son of Mexican actress Lupe Mayorga) formed the Mexican rock and roll band 'Los Nomadas' in East Los Angeles, California and played at dances, shows, and concerts to help raise money for the cause. When Garcia appeared before the Supreme Court on January 11, 1954, Chief Justice Earl Warren gave him sixteen extra minutes to present his argument. The Supreme Court voted unanimously in favor of Hernandez.