Leonardo's apprenticeship under Andrea del Verrocchio was his first significant employment. Verrocchio provided him with training, resources, and opportunities to collaborate on projects, laying the foundation for his artistic career.

Leonardo served as a court artist, engineer, and advisor to Ludovico Sforza, the Duke of Milan. He undertook numerous projects, including the design of military fortifications, stage sets, and paintings such as "The Last Supper". This was a long and fruitful period of employment.

Leonardo briefly worked for Cesare Borgia as a military engineer, surveying and designing fortifications in central Italy. This employment was short-lived but exposed him to military strategies and political intrigue.

The Florentine government commissioned Leonardo to paint "The Battle of Anghiari" in the Palazzo Vecchio. This prestigious commission demonstrated the Republic's recognition of Leonardo's artistic talent, although the project was ultimately unsuccessful.

Leonardo returned to Milan at the invitation of Charles d'Amboise, the French governor. He continued his artistic and scientific pursuits under French patronage, though specific commissions are less documented than during the Sforza era.

Leonardo worked in Rome under the patronage of Pope Leo X, although his activities during this period are not well documented. He likely pursued scientific studies and anatomical investigations, but major artistic commissions were limited.

Leonardo spent his final years in France at the invitation of King Francis I, who provided him with a residence and generous support. Leonardo continued his studies and artistic pursuits, serving as an advisor to the king. This was a period of relative leisure and intellectual freedom.