English molecular biologist whose study (with Jean Hanson) of muscle ultrastructure using the techniques of X-ray diffraction and electron microscopy led him to propose the sliding-filament theory of muscle contraction. An explanation for the conversion of chemical energy to mechanical energy on the molecular level, the theory states that two muscle proteins, actin and myosin, arranged in partially overlapping filaments, slide past each other through the activity of the energy-rich compound adenosine triphosphate (ATP), during muscle contraction.

Huxley worked on the development of radar equipment for the Royal Air Force (1943–47), for which he was made a member of the Order of the British Empire. After the war he received his Ph.D. from Cambridge University (1952), and then worked at the Massachusetts Institute of Technology (1952–54), Cambridge (1953–56), and University College, London (1956–61). In 1962 he became a member of the Medical Research Council's Laboratory of Molecular Biology at Cambridge.