A significant departure from the conventional one-size-fits-all approach is represented by personalized medicine, which is the customization of medical care to each patient's unique traits. This review thoroughly examines the past, present, and future developments of personalized medicine. We examine its fundamental pillars-genomics, pharmacogenomics, and biomarker discovery-and describe their clinical uses in rare illnesses, oncology, cardiology, and psychiatry. The importance of enabling technologies, such as artificial intelligence, big data analytics, and next-generation sequencing, is emphasized. It also discusses the major obstacles to wider adoption, including the need for physician education, regulatory and reimbursement barriers, health fairness and access, and data privacy and security. A more dynamic, predictive, and participative approach to medicine is being made possible by the convergence of wearable technology, digital health technologies, and multi-omics data. Even if science and technology have advanced remarkably, to fully realize PM's promise and guarantee that it benefits all facets of society, concurrent breakthroughs in ethical frameworks, health policy, and interdisciplinary collaboration are required.