<p>Seaweeds, diverse marine macroalgae, are vital for ecosystems, offering significant environmental, nutritional, and economic advantages. Categorized as green, red, or brown based on pigments, they are widely used in food, medicine, and cosmetics. China leads in cultivating approximately 18 species, and innovative farming methods, like integrated multi-trophic aquaculture and advanced offshore systems, are rapidly expanding global seaweed production. This expansion considerably boosts sustainable agriculture, bioenergy, and food security. While seaweeds deliver high-value proteins, vitamins, dietary fibers, and bioactive compounds, and enhance crucial ecosystem services, their sustainable cultivation faces challenges from environmental stressors like ocean warming and pollution. Addressing these requires adaptive strategies, such as selecting resilient species and implementing effective monitoring and management. Biotechnological advancements, including tissue culture, mutation and selective breeding, and genetic engineering techniques like promoter engineering and CRISPR-based gene editing, offer promising avenues to improve yield, stress tolerance, and biochemical profiles. This comprehensive review uniquely integrates seaweed farming practices, nutritional benefits, environmental impacts, and biotechnological innovations with technological applications such as remote sensing, computational fluid dynamics, and numerical modeling for environmental monitoring and agricultural management. By synthesizing these elements, this review promotes sustainable seaweed utilization to address global challenges in food, health, and climate change.</p>