After his father's defeat in the Battle of Montemurlo, Strozzi fled with his brothers to France, at the court of Catherine de' Medici. Later he fought against Cosimo I de' Medici at Siena, but was again defeated.
In 1530, Strozzi became a knight of the Order of Malta, for which he was Prior in Capua. In 1536, he was named commander of the galleys of the Order, a position he held again in 1552. In August 1547 he captured St Andrews Castle in Scotland from the Protestant Lairds of Fife who had killed David Beaton. The lairds knew an expert was in the field when they observed cannon being winched into position with ropes rather than exposing the besiegers to their fire.
|Ancestors of Leone Strozzi|
- Lindsay of Pitscottie, Chronicles of Scotland, vol. 2, Edinburgh, (1814), 489-490.
- Landi, Fausto: Gli ultimi anni della Repubblica di Siena 1525 - 1555, Edizioni Cantagalli, Siena 1994