‘Donatello is the real hero of Florentine sculpture’, so Antony Gormley has proclaimed (hugely though he admires Michelangelo). It’s hard to disagree. But the full range of his work is hard to see, spread out as it is on altars and tombs through Florence and elsewhere in Italy. This makes Donatello: Sculpting the Renaissance at the V&A an unmissable treat.

Throughout much of the Quattrocento, Donato di Niccolo di Betto Bardi (c.1386-1466) – or ‘Donatello’ – turned out new notions about what art could look like and how it might be made. In origin he was, as the V&A show emphasises, a goldsmith. Donatello’s two older friends and colleagues, Filippo Brunelleschi and Lorenzo Ghiberti, also began in that profession.

It has often been said that sculpture was the dynamo of the Florentine Renaissance. That’s true – and it all began with a trio of ambitious metalworkers who turned to sculpture – and, in Brunelleschi’s case, architecture too. With the younger and short-lived painter Masaccio (1401-28), two marvellous pictures by whom are included in the exhibition, this trio of goldsmiths were the founders of the 15th-century Renaissance.

As an artist, Donatello was versatile, prolific, inventive, influential and long-lived (he was around 80 when he died). This gives the V&A exhibition an epic quality. It is littered with masterpieces by or partly by Donatello (he tended to work with a team). But it is also full of works by others, demonstrating how far his influence reached: the way, for example, the painter Fra Filippo Lippi took a Madonna by Donatello as a starting point for one of his own.

Giovanni Bellini, great painter though he was, owed a great deal of his ‘Dead Christ Supported by Angels’ (c.1465) – the composition, the feeling, the mood – to Donatello’s relief of the same subject from Padua. Admittedly, Bellini has added extra elements such as a tender sunset. But the Donatello has such emotional power and concision you don’t miss the sky.

Moreover, when he wanted, Donatello could sculpt nebulous airiness. His delicate ‘Madonna of the Clouds’ (c.1425-35) is an exercise in the technique known as rilievo schiacciato (squashed or flattened relief). You might say here that Donatello was drawing on the marble, except that much of the time he was creating a picture with immensely subtle nuances in the thickness and texture of the stone. In this way he somehow manages to distinguish between the Virgin’s various robes and veils and the surrounding vapour filled with floating cherubim.

Donatello loved these. Chubby toddlers, whether praying, fluttering or wildly dancing, are everywhere – including the disco-putti ecstatically romping on the panels from the Prato pulpit of 1434-8 (the V&A prefers the term ‘spiritelli’, ‘little spirits’ or ‘sprites’, for these creatures).

Sometimes they are angels, sometimes not. Donatello found them in ancient art, but he never simply imitated antiquity. In his work they are transformed into something else, large anarchic babies almost alarming in their energy and freedom. The figure known as the ‘Attis-Amorino’ (see below), trampling a snake at his feet, one of the high points of the show, is a case in point: enthralling but weird.

It is also a tremendous feat of bronze casting, its surface a masterclass in contrasting texture. Which brings us back to Donatello’s beginning as a goldsmith. This was a trade that required its exponents to be versatile. They even functioned as opticians, and combined materials of various kinds in novel ways. This was what Donatello continued to do when he graduated to sculpture.

Michelangelo, his successor as the leader of Florentine art, stressed that his own preferred metier was carving marble. But Donatello was a multimedia man. The so-called ‘Chellini Madonna’ (c.1450), one of the V&A’s own greatest treasures, reveals his delight in the process of casting and moulding. This is a bronze roundel of the Virgin and Child with angels. But, unusually, it works as well when seen from its concave back. Effectively, Donatello presented its first owner – his doctor, Giovanni Chellini – with a kit for making more Donatellos. He could admire front and back of the bronze – or use it to cast a glass replica (such as the one on show).

Seeing many of Donatello’s greatest works is, under normal circumstances, far from easy. The high altar of the Santo in Padua is his magnum opus but can only be observed from a distance. So it is a privilege to be able to peer at some of its component parts from inches away. And a lesson in how much can be packed into a small area.

The relief of ‘Miracle of the Mule’ (c.1446-9), for example, is not much more than a metre wide. But it contains dozens of figures in a complex, vaulted space, including the saint and the devout mule which kneels reverently. Compressed on this rectangle of metal is enough expressive form, imagination and invention to power teams of artists for decades – which was what, in effect, Donatello did.