Joseph Heintz received his early training from a painter and from his father, an architect-mason. From 1584 to around 1591, Heintz was in Italy, where he joined a circle of German and Netherlandish artists in Rome. He also studied ancient art and copied paintings by Renaissance artists such as Raphael, Michelangelo, and Polidoro da Caravaggio. In 1587 he traveled to Florence and Venice, absorbing the styles of Tintoretto, Titian, and Paolo Veronese.
In 1591 Emperor Rudolf II summoned Heintz to Prague, naming him "portraitist and court painter" and ennobling him in 1602. Heintz continued to visit and work in both countries, drawing and copying Italian works of art while serving as Rudolf's art agent and making his own pictures. Heintz's paintings included religious images, portraits, and, following the emperor's taste, erotic mythological themes. Agitated figures, shallow depth, and a cool-toned, colorful palette characterize his very personal style.
Heintz spent his later career primarily as an architect, mainly in Augsburg and Prague. He designed the east facade of Augsburg's new customs house, basing his architectural forms on his father's ideas and on contemporary architecture in Rome, Venice, and Lombardy.