Leonardo is famous for his realistic paintings, such as the Mona Lisa and The Last Supper, as well as for influential drawings such as the Vitruvian Man. He conceived of ideas vastly ahead of his own time, notably conceptually inventing a helicopter, a tank, the use of concentrated solar power, a calculator, a rudimentary theory of plate tectonics, the double hull, and many others. Relatively few of his designs were constructed or were feasible during his lifetime; modern scientific approaches to metallurgy and engineering were only in their infancy during the Renaissance.

In addition, he greatly advanced the state of knowledge in the fields of anatomy, astronomy, civil engineering, optics, and the study of water (hydrodynamics). Of his works, only a few paintings survive, together with his notebooks (scattered among various collections) containing drawings, scientific diagrams and notes.

Leonardo had no surname in the modern sense; "da Vinci" simply means "from Vinci". His full birth name was "Leonardo di ser Piero da Vinci", meaning "Leonardo, son of (Mes)ser Piero from Vinci."

The earliest known dated work of Leonardo's is a drawing done in pen and ink of the Arno valley, drawn on 5 August 1473. It is assumed that he had his own workshop between 1476 and 1478, receiving two orders during this time. From around 1482 to 1499, Ludovico Sforza, Duke of Milan, employed Leonardo and permitted him to operate his own workshop, complete with apprentices. It was here that seventy tons of bronze that had been set aside for Leonardo's "Gran Cavallo" horse statue were cast into weapons for the Duke in an attempt to save Milan from the French under Charles VIII in 1495.