Giovanni Battista Fiera was born in Mantua in 1465. He studied at the University of Pavia, from where he graduated in 1485 with a degree in medicine, but extended his interests to poetry, philosophy, and theology. Moving to Rome after graduation, he published there in 1490 one of the first books on dietetics, La Coena (The Supper). It features discussions and recommendations on the serving and eating of truffles, chicken, apples, quinces, etc, and also of wine. It was widely read and republished several times.

On his return to Mantua, Fiera practiced medicine, but also wrote profusely on other subjects such as jurisprudence. He composed poems, including one on theological subjects, which he dedicated to Pope Leo XX but failed to please him. He later submitted works to the rulers of Venice, but these were also not well received. He died around 1540, solitary and disappointed.

The portrait of Fiera in the National Art Gallery in London is by the Mantuan painter Lorenzo Costa. It dates from about 1510. It has been suggested that Costa suffered from syphilis and painted this portrait of Fiera in return for services provided by the doctor.