Heart transplantation is a critical treatment for end-stage heart failure. However, its clinical efficacy is hindered by some challenges, such as ischemia-reperfusion injury (IRI) and post-transplant rejection. These complications significantly contribute to graft dysfunction and compromise patient survival. Emerging evidence underscores the involvement of proteasome in the pathophysiology of both IRI and post-transplant rejection. Proteasome inhibition has demonstrated potential in attenuating IRI by limiting oxidative damage and apoptosis while also mitigating rejection through the regulation of adaptive and innate immune responses. Recent advances in the development of proteasome inhibitors, particularly in optimizing specificity and minimizing adverse effects, have further strengthened their prospects for clinical application. This review focuses on the roles of the proteasome and its inhibitors in heart transplantation, with an emphasis on their mechanisms and therapeutic applications in managing IRI and rejection.