Hodgkin was educated at Trinity College, Cambridge. After conducting radar research (1939–45) for the British Air Ministry, he joined the faculty at Cambridge, where he worked (1945–52) with Huxley on measuring the electrical and chemical behaviour of individual nerve fibres. By inserting microelectrodes into the giant nerve fibres of the squid Loligo forbesi, they were able to show that the electrical potential of a fibre during conduction of an impulse exceeds the potential of the fibre at rest, contrary to the accepted theory, which postulated a breakdown of the nerve membrane during impulse conduction.

They knew that the activity of a nerve fibre depends on the fact that a large concentration of potassium ions (potassium) is maintained inside the fibre, while a large concentration of sodium ions (sodium) is found in the surrounding solution. Their experimental results (1947) indicated that the nerve membrane allows only potassium to enter the fibre during the resting phase but allows sodium to penetrate when the fibre is excited. (See also action potential.)

Hodgkin served as a research professor for the Royal Society (1952–69), professor of biophysics at Cambridge (from 1970), chancellor of the University of Leicester (1971–84), and master of Trinity College (1978–85). He was knighted in 1972 and admitted into the Order of Merit (Merit, Order of) in 1973. Publications by Hodgkin include Conduction of the Nervous Impulse (1964) and his autobiography, Chance and Design: Reminiscences of Science in Peace and War (1992).