Malus was born in Paris, France. He participated in the expedition into Egypt, 1798 to 1801. Malus became a member of the French academy of sciences in 1810.
His ground-breaking contribution in Optics was to define a measure (orientation angle) by which to characterize relations between a light source and a system of detectors. In applying such basic measurements, Malus determined the reflectivity of various sets of surfaces, and the birefringence of various translucent media.