Advanced technology is not only transforming the public sector in general but is also increasingly transmuting the criminal justice system. Smart applications are designed to predict crimes, automate legal proceedings, and predict recidivism. We argue that such use of intelligent technology to optimize police work, criminal justice, and law enforcement is ultimately serving to establish a “smart criminal justice.” However, not every use of technology is intelligent or “smart,” per se. Based on a literature analysis, we explore the meaning of “smartness” from a descriptive and normative perspective, in order to develop a catalog of decisive criteria. We identify the use of technology as a basic prerequisite, and efficiency, effectiveness, and participation as normative criteria for any smart initiative in the public sector. Considering the specifics of the criminal justice system, these criteria can be expanded by claims related to legality, equality, and transparency. In sum, this article presents and discusses guidelines for assessing the usefulness and legitimacy of technical innovations in the criminal justice system. The catalog developed here will facilitate practitioners and policy-makers in determining when the use of technology in criminal justice is actually smart, and more importantly, when it is not. Points for practitioners Advanced technology is increasingly being used in the public sector in general and the criminal justice system in particular, bringing opportunities as well as substantial risk. The use of technology has to adhere to normative principles to be considered as “smart criminal justice.” This article presents a list of normative criteria that can be used in practice to assess whether technology in criminal justice is used smartly. Practitioners are encouraged to use this catalog as a guide for procurement, implementation, and evaluation processes.