The castle is powerful and compact in its size with very little decoration - one square compound built in red bricks, one of the most prominent examples of Gothic architecture of the age, with imposing M-shaped merlons running along the castle and bridge walls. It has seven towers, a superelevated keep (maschio) with four main buildings inside. The castle is surrounded by a ditch, now dry, which was once filled with waters from the nearby Adige.
Castelvecchio is now home to the Castelvecchio Museum and the local officer's club which can be accessed through the left door on Corso Cavour.
The castle stands on the probable location of a Roman fortress outside the Roman city. Lord Cangrande II della Scala had it built along with its bridge across the Adige River as a deterrent to his powerful neighbors such as Venice, the Gonzaga and the Sforza families. Construction was carried out between 1354 and 1376 (Cangrande died in 1359). The fortified bridge was intended to allow the seigniors to escape safely northwards to the Tyrol in the event of a rebellion or a coup d'état (the Scaligeri were allies of the Holy Roman Empire) and when they eventually lost their hold on Verona, its surviving members left Italy to found a German branch of the family.
Later, during the Venetian domination, slits were added to defend it with cannons. The castle was damaged by French troops during the Napoleonic Wars (1796-7), in retaliation to the Pasque Veronesi, when the local population staged a violent anti-French revolt. Napoleon had chosen to stay in Castelvecchio on his trips to Verona, but his widespread and arbitrary requisitions of citizens' and churches' property, the massive draft of male workers into the French army prompted the resistance that eventually drove out the invaders.
Under the Austrians, Castelvecchio was turned into barracks. In 1923 the castle was restored, as well as in 1963-1965.