How do private companies justify taking on criminal justice functions? Building on writing on legitimacy and privatization, this article describes three rhetorical practices intended to increase the legitimacy of private companies carrying out criminal justice functions: softening (obscuring the use of force); shrinking (demonstrating deference to the state); and signaling (proclaiming alignment with pro-social values). The article demonstrates the analytic utility of these categories by considering public-facing Environmental, Social, and Governance (ESG) reports produced by one prominent company in the private corrections industry (CoreCivic). The conceptual typology of legitimation work brings together several dynamics that are common in privatized criminal justice and provides an analytic toolkit for future study. A discussion considers how researchers can use this typology to examine legitimation work by other private firms and industries that engage the criminal justice system.