Leading member of an artistic dynasty in Cremona, Giulio Campi trained his much younger brother, with whom he sometimes collaborated; his own sons; and a group of pupils who dominated Cremonese painting in the last half of the 1500s. According to Giorgio Vasari, Campi learned painting from his father, though his early creations were also indebted to Pordenone's Mannerist style.
Around 1539, Campi and his rival were both painting decorations in Cremona's church of San Sigismondo. In this competitive context, Campi created some of his most energetic works. His frescoes and altarpiece typify an eclectic style combining Giulio Romano's monumental classicism with the elegant, sensuality of Parmigianino, influences also displayed in his rival's nervously rhythmic frescoes. Together the two competitors designed and constructed decorations for Emperor Charles V's 1541 triumphal entry into Cremona. When Campi returned to San Sigismondo in the late 1550s, his style showed a greater monumentality and more daring illusionism, suggesting a recent visit to Rome. In his last years he painted regularly for Cremona Cathedral.