Musée du Louvre, Paris, Département des Arts Graphiques

A Fete at Saint-Cloud (ca. 1760), a drawing on display at the Frick Collection’s exhibition of the works of Gabriel de Saint-Aubin (1724-1780), depicts an 18th-century Parisian bal champêtre, or outdoor ball. Set in the grandiose Parc de Saint-Cloud with the magisterial staircase of the Grande Cascade as its backdrop, the young men and women of fashionable society display their good breeding. Saint-Aubin employs pen, brush, ink and chalk with offhand ease to bring the revelry to life. An obscured, sketchily delineated peddler is the only indication of a life beyond leisure.

Saint-Aubin, who had access to elite society and admired its elegance, rendered many of his drawings from direct observation. But you have to wonder how he convinced French socialites to let him come within drawing distance: Saint-Aubin was, by all accounts, a slob. The official responsible for inventorying Saint-Aubin’s work after his death, for example, was so disgusted by the state of the artist’s studio and lodgings that he refused to enter until it was cleaned out.

Pierre Rosenberg, former director of the Louvre, excuses Saint-Aubin as a “free spirit,” a proto-bohemian for whom art was more important than bathing. Yet Saint-Aubin’s looks did not, in the classic bohemian manner, redeem his personal habits. The artist’s features, according to Mr. Rosenberg, were “bovine,” or even, in an apparent compliment to cows, “ovine.” Sophie Arnauld, a grande dame of the Paris Opera and acquaintance of Saint-Aubin, agreed, telling the artist’s brother that “[Saint-Aubin] has no teeth, he daubs more than he dents.”

AS A PAINTER, Saint-Aubin encountered rejection early on. He repeatedly lost the competition for the Grand Prix for history-painting while studying at the Académie Royale, missing the opportunity to further his training in Rome. On the slim evidence at the Frick, Saint-Aubin was a technically able but thoroughly cloying painter—an artist whose taste for anecdote stifled pictorial unity. The blur of clouds in the upper right-hand corner of The Poet’s Reward (ca. 1759), for instance, is ham-handed and fudgy. Even a fan like Mr. Rosenberg has to commiserate with the jury who gave Saint-Aubin a thumbs-down for entry into the Ecole des Elèves Protégés.

This failure was, according to the writers Jules and Edmond de Goncourt, a turning point in Saint-Aubin’s career: “In a single day he left [the Academy] behind, bestirred himself, turned over a new leaf, lost ambition, refashioned his idols” and became an artist “seeking beauty in what was before his eyes, the spectacle of eighteenth-century Paris.”

Saint-Aubin turned his full attention to drawing, earning a reputation for fantastic productivity as a draftsman. The painter Jean-Baptiste Greuze, a contemporary, noted Saint-Aubin’s “priapic urge to draw.” Another observer wrote that Saint-Aubin “drew … anytime, anywhere, with an unparalleled passion.” The artist’s brother Charles, a not altogether reliable source (but a consistently entertaining one), numbered the drawings between 4,000 and 5,000.

His hand was sure. Unafraid of mixing media, Saint-Aubin rarely confined himself to a single drawing tool. In The Naval Battle near Economus (256 B.C.) (ca. 1763) and The Triumph of Pompey (61 B.C.) (ca. 1765), the failed history painter conjures dramatic miniaturist panoramas from seamless drifts of watercolor, gouache, pen, and black and brown ink over a ground of chalk. Even when his mode is ascetic, he demonstrates a gift for eliciting the best of several mediums at once.

Though adept at drawing in a loose-limbed, open and airy manner—a portrait of his niece and nephew is a charming example—Saint-Aubin is most remarkable when he is most meticulous. Many of the drawings at the Frick beggar the eye. A nearby rack of magnifying glasses will help you appreciate Saint-Aubin’s detailing, whether architectural or figurative, but won’t diminish your amazement at exactly how he did it. How small, exactly, was his pen nib? Notes and jottings at the bottom of several sheets are elegantly placed, but their razor-thin width makes them all but indecipherable.

The unfinished The “Salon du Louvre” in 1765 (1765) is a tour de force because of its unfinished state. We see the drawing begin from the ground up with roughed-in figures here, more developed items there and all-but-complete depictions of paintings that were included in the “Salon” exhibition named in the title. Viewers will delight in narrative particulars (including, it would appear, a couple getting it on) and be awed by how convincingly Saint-Aubin captures the Louvre gallery’s architectural sweep. More incredibly, the dozens of paintings included in the drawing have all been identified—dazzling testament to this minor artist’s winning virtuosic gift.

“Gabriel de Saint-Aubin (1724-1780)” is at the Frick Collection, 1 East 70th Street, until Jan. 27.