Microalgae represent a prolific reservoir of structurally diverse bioactive compounds, among which photosynthetic pigments such as chlorophylls, carotenoids and phycobilins hold exceptional biomedical and nutraceutical significance. Beyond their primary photoreceptive roles, these pigments exhibit multifaceted biological properties encompassing potent antioxidant, anti-inflammatory, anticancer, antidiabetic, neuroprotective and cardioprotective effects. Their natural origin, high biocompatibility and biodegradability position them as sustainable alternatives to synthetic additives in the food, pharmaceutical and cosmetic industries. This chapter provides a comprehensive overview of the biochemical composition, biosynthetic mechanisms and physiological functions of these pigments, highlighting recent biotechnological advancements in algal cultivation, pigment extraction, purification and stabilisation. It further delineates their pharmacological and nutraceutical potentials, underscoring their therapeutic relevance in mitigating oxidative stress–related disorders. Additionally, this chapter critically addresses the translational gap between laboratory-scale discoveries and industrial-scale commercialisation, emphasising existing challenges in large-scale production, regulatory compliance and consumer acceptance. By integrating biochemical insights with emerging technological innovations, this work elucidates the pivotal role of algal pigments as next-generation natural health-promoting agents, bridging marine biotechnology with global health and sustainability imperatives.