Schiaparelli was born at Savigliano in Italy. After graduating from Turin in 1854, he studied under Johann Encke in Berlin and Friedrich Struve in St. Petersburg. In 1860 he became director of the Brera Observatory, Milan, where he remained until he retired in 1900.

Schiaparelli worked mainly on the solar system, discovering the planetoid Hesperia in 1861. He contributed to the theory of meteors when he showed in 1866 that they follow cometary orbits. He also made careful studies of Mars, Venus, and Mercury. In 1877 Mars approached Earth at its nearest point, a mere 35 million miles. He observed what he called ‘canali’. In Italian this means not ‘canals’ but ‘channels,’ but the word was mistranslated into English as the former, which led to much controversy. Schiaparelli himself was neutral as to their origin. He would not rule out that they were constructed rather than natural but nor would he conclude from their geometrical precision that they were buildings, for he pointed out that other examples of regularity, such as Saturn's rings, had not been man-made. It was other astronomers, such as Percival Lowell and Camille Flammarion, who made extravagant claims about the ‘canals’, not Schiaparelli.

After detailed observations of Venus and Mercury he announced that their period of axial rotation was the same as their sidereal period (the time taken to orbit the Sun, relative to the stars). Thus they would always keep the same face to the Sun. It was not until the early 1960s that this view was disproved, and then only by the use of sophisticated radar techniques.