Global warming is induced partly by rising atmospheric carbon dioxide levels, calling for sustainable methods to sequester carbon. Here we review carbon capture, usage, and storage with microalgae, with focus on methods to improve carbon dioxide uptake, systems combining wastewater and flue gases, machine learning for strain identification, artificial intelligence and automation, and the circular bioeconomy. Carbon dioxide uptake by microalgae can be improved by using modified photobioreactors, membranes, chemical methods, solvents, adapted strains, genetically engineered strains, omics, and nanotechnology. We also discuss the economic viability of microalgae-based carbon capture and bioenergy generation. On an average, microalgal farming on 13 million acres area can sequester approximately 0.5 gigatons of CO2 to generate more than 300 tons of biomass.