GLOUCESTER — Looking at a Stuart Davis painting can feel like seeing sound — bright, ebullient, jazzy, kinetic, a jangle of overlapping notes cohering — often barely — into a symphonic, exhilarating whole. I don’t know if that’s true of any picture so much as “Swing Landscape,” his big, boisterous 1938 painting bursting with color and form (it’s a shade larger than 7-by-14 feet). Hunt and peck all you want — rooftops and smokestacks, ropes and chains, sea and sky? — but the racket drowns out anything like a landscape, title be damned. Unless you’re Stuart Davis. Then it’s Gloucester Harbor, through and through.

Davis, born in Philadelphia, raised in New Jersey, and best known as a particularly bubbly figure of New York’s mid-century Modern avant-garde, was a devout part-time Gloucester resident, summering here for some 20 years from the mid-1910s. Even when his time here became less frequent — his summers stopped in 1934, though he visited as often as possible — he took Gloucester with him wherever he went. You’re not wrong to see gulls and bright skies and New England rooftops in the sparkly pinks and blues of “Midi,” from 1953 to 1954, or in the gleeful tangle of 1952′s “Rapt at Rappaport’s,” with its nautical flag motifs layered and flapping. (In Davis’s best paintings, you can almost smell the sea breeze.) But “Swing Landscape” is his magnum opus, his Gloucester ode. It feels simultaneous, like everything he did and saw here let loose all at once. Its clamor is tonic, an unchained joy.

Was Davis always so much sunshine, such a bundle of unfettered glee? Hardly. In 1913, when he was just 20, Davis’s work was slipped into New York’s influential Armory Show under the auspices of his mentor, the Ashcan School painter John Sloan, who saw in Davis a talent as obvious as the nose on his face. But at the show, Davis was less interested in what he’d made than what he saw. The Armory that year was a landmark in Modernism’s breakthrough to the mainstream, a North American coming out party for European radicals like Henri Matisse and Pablo Picasso. In them, Davis saw the future — Matisse’s otherworldly colors, Picasso’s broken perspectives and fractured forms — though it would take time for their influence to surface. Dizzied, Davis returned to the dour realist cityscapes he’d been painting, a carryover of his Ashcan mentorship from Sloan and Robert Henri, a family friend of his artist parents. But the slow burn had begun.

In 1915, Sloan invited him to spend a summer at the burgeoning art colony in Gloucester. Davis had already been to Provincetown, another fertile creative cluster, where he encountered Charles Demuth, then part of Alfred Stieglitz’s 291 gallery of American proto-Modernists. Davis had fallen for Demuth’s ideas, for the dreamy North Atlantic summer light. Less enthralling were the soft textures of Cape Cod, with its dunes and endless powdery beaches. But on the craggy Cape Ann coast, Davis wrote, he found “the same brilliant light ... but with the important additions of topographical severity and the architectural beauties of the Gloucester schooner.” He called it, simply, “the place I had been looking for.”

That first summer, Davis joined Sloan and his wife, Dolly, in the red clapboard East Gloucester cottage that would become an informal clubhouse for the generation of artists who saw in Cape Ann possibility and freedom. Gloucester had drawn painters since at least the middle of the 19th century — Fitz Henry Lane, a Luminist master, was a native son; Winslow Homer had been enthralled by the varied landscapes and captivating color and light in the 1870s. And by the turn of the century, American Impressionists like Childe Hassam made it a favorite place to paint en plein air.

Davis holed up on Rocky Neck, a charmingly disheveled collection of fishing shacks with a growing community of studios and galleries. (“The artists,” read an article in the Cape Ann Shore newspaper of the day, “have elbowed out the fishing interests,” having “in the past decade completely changed the complexion of things at Rocky Neck.”) His early works here speak of the hardscrabble toughness of a fishing village carved into the rough granite of the Cape Ann shore. They were Ashcan works, transposed from city to sea: “The Morning Walk (Harbor View),” 1919, piles up little clapboard cottages between the boulders, looking back from Rocky Neck over Gloucester Harbor at gray waters, with trees the color of rust. Another from the same year, simply titled “Gloucester,” shows a man hiking in solitude amid undulations of leathery earth and bushes yellowing with autumn, the pale sea in the distance under pallid skies.

What Davis found here, as much as anything, was his groove. New York would fill him up with its rhythms — of thick traffic and teeming humanity, of the jump and verve of the jazz he so loved — and Gloucester would let it all out. Over time, his dour images transformed, slowly at first, into expressive landscapes like the Van Goghs he saw at the Armory — heavy brushstrokes yielding thick mounds of rock and bush. They came to brim with Matisse-like colors, and to flatten and fracture into Picasso-like contortions — though Davis eschewed the jagged, violent undertones the Spaniard’s pictures often carried. (“I was a cubist,” Davis once quipped, “until someone threw me a curve.”)

At Rocky Neck today, you still find galleries huddled together along the shoreline on Smith’s Cove, and the Cultural Center at Rocky Neck is both the keeper of local lore and an advocate for preserving this artist’s haven. The history is rich — Davis either crossed paths with or came close to Mark Rothko, Barnett Newman, Edward Hopper, and Milton Avery here. But the past is no armor against the present. The workaday charms of Gloucester Harbor — the clutter and verve that drew Davis’s eye — remain, but time hasn’t stood still.

On the Harbor side of the Neck, on my way out to the weather-beaten wharf where the nonprofit Ocean Alliance has its headquarters, my jaw dropped at the conference center-size new mansion looming on the rocky ledge above. That its next-door neighbor was the regal Victorian captured in “The Mansard Roof,” Hopper’s own Gloucester ode from 1923, put a fine point on it.

That picture, stately and haunting, with clapboards bleached by wind and sun, was made just as Davis was finding his feet. There’s a stutter in the early ’20s, a dodge and feint; Davis’s “Wharf,” from 1921, with its heavy shadows and collapsed forms, feels surly, bristling with menace. But then he’s off — painting sail lofts and lighthouses with a crisp and sparkly exuberance, an all-American Cubism entirely his own.

I look at “Gas Pumps,” from 1925, and I can hear the waves slapping the rocks, the flutter of flag on the breeze. A Davis work always feels slightly in motion — like it’s been caught in the act, but doesn’t care. Which brings us back to “Swing Landscape” — peak Davis, the one for which he’ll forever be known. It’s one of those paintings where you just want to stay out of its way, where every effort to parse just slows it down. You don’t want to do that. This is Davis at full speed, a collision of color and sound and experience, all vibrating in dizzying unity.

“Swing Landscape” was no breakthrough — Stuart Davis had become Stuart Davis a few years before. The painting, commissioned in 1938 by the New Deal-era Federal Art Project was destined for a housing project in Brooklyn, though it was never installed and ended up with the University of Indiana, where it was welcomed and is treasured still. But it was a culmination and a departure point, a liberating gesture of self-declaration. Everything before led up to it, in fits and starts. Everything after flowed from it, in crisp, clear bursts of dynamic color.

The same year, Davis painted the harbor and called it by name — perky schooners with their sails up, buoys and ropes tangled on the dock, the pinch of the rocky harbor in view. “Gloucester Harbor” feels like a warm-up for the ultimate tribute to the painter’s second home. “Swing Landscape” endures in its kinetic, enigmatic glory — a magnificent, cacophonous clutter, too ebullient to be contained by the rules of logic or even physics. Gloucester gave Davis that: The energy to crave and see and paint everything, all at once. “Swing Landscape” is what he gave back. Is there a love letter more glorious than that?