One of LBJ’s signature civil rights achievements, the 1965 Hart–Celler Immigration Act still stands in providing the overarching structure for immigration regulation in the US today. Its enactment ended decades of overtly racist immigration laws, crowning the almost equally long campaigns by immigration reformers seeking a more egalitarian system. In securing passage of the legislation, LBJ provided essential leadership but accepted significant compromises to do so. The immigration overhaul succeeded in abolishing the most discriminatory aspects of the old system for immigration regulation, even as it has implemented new forms of inequalities that have criminalized migrations particularly from the US’s closest neighbors. This law has transformed the US through the most diverse immigration in national history, even as it has produced a large and persistent caste of second-class residents whose unauthorized immigration bars them from citizenship.