August Krogh was a Danish professor who was conferred with the Nobel Prize in Physiology or Medicine in 1920 for his discovery of the mechanism of regulation of the capillaries in the skeletal muscle. His contribution to understanding the anatomy and physiology of the capillary system has been exceptionally remarkable and noteworthy. A prodigious child, Krogh showed an interest in natural sciences early on his life. It was a lecture by Christian Bohr that made Krogh turn to physiology as his career option. He became a pioneer in comparative studies of animals. Furthermore, he made a number of fundamental and revolutionary discoveries in the fields of physiology, and became famous for developing the Krogh Principle. He served as the Professor of the department of zoophysiology at the University of Copenhagen from 1916 to 1945. Interestingly, Krogh in his lifetime devised a number of instruments and machines that aided in his physiological study. His recording spirometer is till date used in many hospitals, his bicycle ergometer is one of the most valued working machines, his precision pipettes and respiration apparatus improved methods for gas analysis. They reflect a constructive side of Krogh that remained veiled behind his outstanding achievements as a scientist.