Scholarly accounts attribute the American South’s historic partisan transformation that began in the 1960s to a combination of political and economic factors, but no prior work emphasizes the connection between individuals’ fundamental beliefs and partisan change. Using pooled American National Election Studies (ANES) data from 1988 to 2016, we show that egalitarianism and moral traditionalism are more likely to influence southerners’ party affiliation relative to non-southerners. Southerners did not connect their core values to the same extent as other citizens in the early years of our analysis—owing to the vestiges of a one-party system operating in Dixie. But over time, the relationship between core values and partisanship among southerners strengthened remarkably. Moreover, 1992–96 panel data show that egalitarianism in particular influences southern partisanship (but not vice versa). Our results reveal that core values are integral to understanding the southern Republican realignment and southerners’ persistent political distinctiveness.