The work of Cardano constitutes a landmark in the development of algebra and yet in his own time he was chiefly known as a physician. He studied medicine at the University of Pavia, the city of his birth, and at the University of Padua, receiving his degree in 1526. He spent much of his life as a practicing physician, becoming professor of medicine at Pavia in 1543. One of his notable nonmathematical achievements was to give the first clinical description of typhus fever.

It was however in mathematics that Cardano's real talents lay. His chief work was the Ars magna (1545; The Great Skill) in which he gave ways of solving both the general cubic and the general quartic. This was the first important printed treatise on algebra. The solution of the general cubic equation was revealed to him by Niccolò Tartaglia in confidence and Cardano's publication aroused a bitter controversy between the two. Cardano's former servant, Lodovico Ferrari, had discovered the solution of the general quartic equation. In his later Liber de ludo aleae (Book on Games of Chance) Cardano did some pioneering work in the mathematical theory of probability.

Cardano's interests were not, however, limited to mathematics and medicine. He also indulged in philosophical and astrological speculation and this had the unfortunate consequence that in 1570 he was charged with heresy by the Church. He was briefly jailed but was soon released after the necessary recantation. As a result of this episode Cardano lost his post as a professor at the University of Bologna, which he had held since 1562.