In the 21st century, the world faces growing environmental and energy challenges, including rising carbon dioxide emissions (exceeding 420 parts per million), water pollution from excess nutrients (nitrogen and phosphorus), causing ecological imbalance, and a 45–50% increase in global energy demand by 2050. Microalgae offer a comprehensive solution thanks to their high photosynthetic efficiency (8–10%), high productivity (50–70 g/m²/day), and ability to produce valuable compounds such as lipids, proteins, and pigments. Bubble column reactors (BCRs) are considered the most attractive option for industrial applications due to their low energy consumption (0.2–2.0 kW/m³ compared to 1–15 kW/m³ for mechanical systems), low shear stress (less than 5 Pa), and a volumetric gas transfer coefficient ranging from 0.01–0.035/s, in addition to absence of mechanical stress, simple design, and high gas transfer efficiency. This research reviews strategies for improving productivity, such as optimizing lighting, gas flow, and the use of wastewater as a nutrient source, as well as incorporating packing media that increase the surface area by up to 56%. It also covers wastewater treatment applications (removal of nitrogen, phosphorus, and heavy metals), carbon dioxide capture from industrial gases, and the production of biofuels, animal feed, fertilizers, and high-value dyes. Despite the progress made, challenges remain regarding harvesting efficiency, light distribution at large scales, and long-term stability. The research concludes that bubble column reactors represent a promising path toward a low-carbon circular bioeconomy, particularly when combined with advanced automation and process control.