This article offers an exhaustive overview of micro‑encapsulated phase‑change materials (PCMs), addressing thermal‑energy storage mechanisms, operating principles, classifications (eutectic, inorganic, organic), encapsulation techniques, shell materials, fields that incorporate microencapsulated additives—including textile applications—and drawing on more than 50 up‑to‑date sources. Microencapsulation encloses active agents within ultra‑small capsules, a method already utilized in textiles, agriculture, printing, food processing, and defense sectors; PCMs store or release substantial latent heat when shifting between solid and liquid states. Challenges arose in harmonizing disparate synthesis pathways and core‑shell pairings from various disciplines and in surfacing safety issues scattered throughout the literature. Nonetheless, the work contributes by systematically grouping PCMs and shells, compiling physical, chemical, and physico‑chemical encapsulation methods into a comparative decision matrix, illustrating organic PCMs’ textile superiority despite reduced fabric strength, expanding application maps to biomedicine, solar‑to‑thermal and electric‑to‑thermal storage beyond buildings and aerospace, and assembling over 50 studies into one consolidated reference. Thus, microencapsulation proves to be a flexible platform for customizing PCMs toward efficiency, safety, and broad practical deployment—paving the way for advanced energy solutions.