For the artist Andrea del Verrocchio, a breakout global show has been a long time coming. But after more than 500 years, the Renaissance master and teacher of Leonardo da Vinci finally is getting what organizers call his first world-wide exhibition.

“Verrocchio, Master of Leonardo” opens in Florence on March 9 at the Palazzo Strozzi and the nearby national Bargello Museum. Later this year, some of the works will travel to the National Gallery of Art in Washington, where they will join others for “Verrocchio: Sculptor and Painter...