Exosomes have emerged as key mediators of intercellular and inter-organ communication. Although substantial advances have expanded the understanding of the biology of extracellular vesicles, exosome biogenesis and their role in the disease progression of systemic diseases have not yet been fully elucidated. In this review, we present a comprehensive overview of the molecular pathways responsible for exosome biogenesis, emphasizing how the selective incorporation of proteins, lipids, metabolites, messenger RNAs, and microRNAs (miRs) determines the composition and biological activity of exosomes. We also discuss how exosome-mediated inter-organ communication functions as an integrated biological network that connects the kidney, the cardiovascular system, the brain, the liver, the immune system, and tumors, thereby coordinating the pathological responses underlying the progression of chronic diseases. Additionally, we demonstrate the recent advances in the potential of exosomes as minimally invasive biomarkers and clinical translational implantation. Finally, we discussed the methodological and biological challenges that limit the clinical application of exosomes. Overall, this review presents an integrated framework for understanding exosome biology and supports the concept that exosomes function as dynamic platforms for systemic signaling that link molecular mechanisms to disease pathogenesis and translational medicine.