The sculptor Juan Martínez Montañés modeled a statue on one of Velázquez's equestrian portraits of the king, painted in 1636, which was cast in bronze by the Florentine sculptor Pietro Tacca and which now stands in the Plaza de Oriente at Madrid.
Po vrnitvi v Madrid je Velázquez naslikal številne portrete mladega princa in dediča španskega prestola.