Out of respect for Francesco Salviati, his irascible mentor, Giuseppe Porta called himself Giuseppe Salviati. From 1535 Porta apprenticed with Salviati in Rome, assisting with decorating facades. The serious tone and sculptural quality of Salviati's figure style remained with Porta for life.
Arriving with Salviati in 1539, Porta spent most of his career in Venice, where his painting absorbed local influences. Salviati left in 1541, but Porta stayed on, becoming famous for his decorations on palazzo facades, none of which survive. He also decorated numerous religious buildings, painting vast ceilings of illusionistic figures. For his altarpieces, Porta adopted the traditional Venetian oil technique of modeling figures using multiple layers of paint. In 1565 Porta returned to Rome to complete the Vatican frescoes left unfinished at Salviati's death. The following year he was elected to Florence's Accademia del Disegno and completed his most important commission: a ceiling fresco in Venice's ducal palace, destroyed soon afterward. In later years, he devoted time to other interests, such as his mathematical accomplishments.