Curzio Picchena was invited into the Council of State at a very early age, under the protection of Belisario Vinta (1542-1613), and was groomed initially for a diplomatic career and sent as Embassy Secretary to France, Spain and Switzerland. From 1601 to 1613 he was Secretary to the Grand Duke and at Vinta's death was appointed Secretary of State. He was highly esteemed by Cosimo II (1590-1621), and, together with Andrea Cioli (1573-1641), took part in the Regency which ruled during the childhood of Ferdinando II (1610-1670).

In the period he was Secretary of State he cultivated a relationship with Galileo, accompanying him during his mission to Rome in 1615/1616, and was involved in the negotiations, never concluded, with the Spanish authorities over Galileo's formula for calculating longitude at sea.

In 1621 Picchena was elected senator, but owing to a rivalry with Andrea Cioli was shortly afterwards removed from Court, and hence devoted his last years to scholarly pursuits. He died on June 14, 1626.