Algae are rich sources of polysaccharides such as alginates, carrageenan, and agar. Commercial applications of algal biomass are primarily in energy production, new functional foods, and medicines. Soil algae help to fix atmospheric CO2 in soil and are primarily present on the surface of the soil to prevent soil erosion. Seaweed contains essential nutrients and bioactive compounds that have pending or potential applications in animal and human health and wellness. Various seaweed and seaweed extracts have been proven to have antibacterial, anti-diabetic, antiviral, antifungal, and antibacterial capabilities. Using algae for the extraction or bioconversion of pollutants such as nutrients and xenobiotics in polluted water and CO2 in polluted air currents is known as phycoremediation. Seaweed, which is commonly used in wastewater treatment, also helps to lower or eliminate hazardous heavy metal levels. The chapter delineates the contribution of algae toward sustainable development and commercial aspects of algae in fuel, medicine, and food applications.