Scheele, who came from a poor background in Straslund (now in Germany), received little schooling and was apprenticed to an apothecary in Göteborg when he was 14 years old. In 1770 he moved to Uppsala to practice as an apothecary. He met and impressed Torbern Bergman, the professor of chemistry there, and was elected to the Stockholm Royal Academy of Sciences in 1775. Also in 1775 he moved to Köping where he established his own pharmacy.

In 1777 Scheele published his only book, Chemical Observations and Experiments on Air and Fire. In this work he stated that the atmosphere is composed of two gases, one supporting combustion, which he named ‘fire air’ (oxygen), and the other preventing it, which he named ‘vitiated air’ (nitrogen). He was successful in obtaining oxygen in about 1772, two years before Joseph Priestley. He also discovered chlorine, manganese, barium oxide, glycerol, silicon tetrafluoride, and a long list of acids, both organic and inorganic, including citric, prussic, and tartaric acids. One further piece of work that had unexpectedly important consequences was his demonstration of the effects of light on silver salts.

Despite receiving many lucrative offers from Germany and England, Scheele remained at Köping for the rest of his life devoting himself to his chemical researches. Although his work must have suffered from his isolation, and he lost priority in many discoveries owing to delay in publication, he is still frequently referred to as the greatest experimental chemist of the 18th century.