Microalgae, as an efficient and sustainable biological resource, have demonstrated great potential for application in various fields such as food, medicine, and cosmetics due to their unique metabolic mechanisms and abundant functional components including proteins, unsaturated fatty acids, pigments, polysaccharides, and polyphenolic compounds. This review explores the latest advances in cell disruption techniques for the extraction of functional components from microalgae with a special focus on mechanical, physical, chemical, enzymatic, and combined methods, as well as their effects on the extraction efficiency. The major bioactivities of microalgal functional components including antioxidant, antimicrobial, immunomodulatory, lipid-lowering, antidiabetic, and anticancer properties are summarized along with their mechanisms of action in health promotion and disease intervention. Furthermore, the current status of the application of microalgae resources in the food, pharmaceutical, and cosmetic industries is reviewed, and the technical challenges and limitations of their industrialization are analyzed. Optimizing the extraction process, delving deeper into the mechanisms of the bioactivities, and promoting industrial applications across multiple sectors will enable microalgal functional resources to provide greater support for the health industry and sustainable development. This article offers a theoretical foundation and practical guidance for the development and multifaceted application of microalgae resources.