Effective recruitment and onboarding are crucial for optimizing new hire performance and organizational success in the contemporary business landscape. This research compares the effect of traditional versus AI-powered onboarding processes on new hire performance through the lens of procedural justice and onboarding success. The research comprises two distinct studies conducted in a private-sector organization within the EU. Study 1 was carried out with N = 154 new hires who underwent traditional onboarding, while Study 2 included N = 112 new hires who went through an AI-powered onboarding. Mediation analysis revealed that in traditional onboarding, perceived procedural justice directly enhances new hire performance, with supervisors’ justice affecting performance evaluations independently of onboarding success. Conversely, in AI-powered onboarding, procedural justice affects performance both directly and indirectly through perceived onboarding success. The latter indicates that AI-driven processes integrate procedural justice and onboarding success, yielding improved performance outcomes. Specifically, new hires who viewed the AI onboarding process as procedurally fair performed better, partly due to their perception of onboarding success. These findings underscore notable differences between hire traditional and AI-powered onboarding methods. Traditional onboarding relies on direct supervisory justice to boost performance, whereas AI-powered onboarding integrates procedural justice with onboarding success, leading to more effective outcomes. The study contributes valuable insights into how onboarding practices can be enhanced through AI, emphasizing the importance of procedural justice and its role in optimizing new hire performance. Organizations may acquire superior performance outcomes by adopting AI technologies in their onboarding processes.