Carbon-based nanocomposites (CNC) with remarkable properties have diverse applications in scientific and technological domains. This review provides an overview of synthesis methods, including chemical vapor deposition, sol-gel synthesis, and self-assembly, also necessitating precise control over composition, structure, and morphology for tailored properties. The review explores the multifunctionality of the CNCs’ in five important areas. In energy storage systems (in supercapacitors and lithium-ion batteries), for improved charge storage capacity and cycling stability. In sensing technologies, CNCs exhibit sensitivity, enhancing the detection of analytes and have been applied in biosensing in medical diagnostics and in environmental monitoring. As catalyst support materials, CNCs enhance efficiency in various catalytic reactions. In nanomedicine, CNCs contribute to drug delivery and imaging with biocompatibility and unique optical properties. Environmental applications of CNCs include water treatment, air purification, and pollutant remediation for sustainable solutions. Critical insights from recent advancements and research studies address challenges and outline future directions have been provided in the review article. In conclusion, this comprehensive review emphasizes CNCs’ transformative impact on energy storage, sensing technologies, catalysis, nanomedicine, and environmental remediation, marking a significant step in addressing contemporary challenges and shaping future technology.