Alfred Ezra Mirsky (October 17, 1900 – June 19, 1974) was an American pioneer in molecular biology. Mirsky graduated from Harvard College in 1922, after which he studied for two years at the Columbia University College of Physicians and Surgeons until 1924 when he moved to the University of Cambridge on a US National Research Council fellowship for the academic year 1924–1925. He received his PhD from Cambridge in 1926, with a dissertation under Lawrence J. Henderson on the Haemoglobin molecule, completing work begun under Joseph Barcroft.