NEW YORK — Winslow Homer, dour and hermetic, spent the last decades of his life perched in his small studio above the sharp stone ledges of Prouts Neck, Maine. “Mr. Homer is NOT at home,” read a sign posted at his fence — a deterrent — though he almost always was. Hordes of tourists came and went with the seasons, and even his family, right next door, decamped for warmer climes in the bitter winter months. But he would die here in 1910, amid paint and canvas, just steps from the sea that was his most constant companion.

Homer had led whole lives before then, east to west, north to south; he criss-crossed the Atlantic, tracing the routes that for two centuries had moved goods and people as colonialism advanced and the world brutally broke open.

He lived in those fractures, a clear-eyed chronicler of the discord within. “Winslow Homer: Crosscurrents,” at the Metropolitan Museum of Art, follows Homer deep inside, charting a narrative arc inscribed by the conflicts that shaped his life. For an artist so often seen in pieces — his last full retrospective was in 1995 — “Crosscurrents” is a rare completist’s view. With its 88 pictures, it has a destination in mind: “The Gulf Stream,” 1899 (reworked 1906), Homer’s remarkable painting of a resolute-looking Black man alone in a broken boat, buffeted by seas thick with sharks in the face of an oncoming storm. You can see it from the start, but only at a distance: It’s hung two rooms away, made visible by big frame-shaped incisions in the walls. It’s like a view through the wrong end of a telescope, a far point with a journey implied. This exhibition is its map.

Homer is on almost-constant view in New England (born in Boston and raised in Cambridge, he’s one of us), but “Crosscurrents” reveals his life’s work as a single enterprise, wound around a core of restless dread that never left him. How could it? Homer, self-taught, began his career embedded with the Union Army during the Civil War, making drawings for Harper’s Weekly to keep northerners up to date. “Sharpshooter,” his iconic small oil painting from 1863, starts things off. A tight scene of the shooter taking aim from a tree, the soldier looks how the artist might have felt: vulnerable and trapped.

The opening section, called “War and Reconstruction,” lays the foundation of Homer’s shift from reporter to artist as his sensitivities betray him. “The Brush Harrow,” from 1865, is withering, two boys tending a barren southern field with a bony horse. Under a bright blue sky, the scene is unnaturally dark, implying violence, a land and lives scarred by war.

Back home in New England, Homer, not yet 30, abandoned commercial illustration to build his painting career. He found himself marked by experience, witness to a foundering, changing world that tainted even bright pictures with palpable anxiety. Homer attempted bucolic scenes and seaside idylls, but they’re imprinted with the resonant bleakness of what I’ve always imagined to be PTSD: The two children in “Crossing the Pasture,” 1871-72, are tense and joyless in a verdant mountain valley; the three women squeezing seawater from their hair and clothes in “Eagle Head, Manchester, Massachusetts (High Tide),” 1870, are blank and inscrutable. In “An Adirondack Lake,” 1871, a lone figure stands in sun-bleached isolation at the water’s edge, looking as though he might dissolve.

Homer returned to the South in the mid-1870s, seeking in Reconstruction the grand tableaux that would make his career. What he found was devastation, a match to his darkened mood. His paintings of Black subjects — taut, sympathetic, charged with the failures of reunification — are among the most powerful he would ever make. “The Cotton Pickers,” 1876, singled out here, is one of those: Two women tend a field, now as paid labor, the disappointment of incomplete freedom carved in their features as if in stone. The gaze of the woman on the right, relayed to some unknowable far point, contains “the whole story of southern slavery,” said Homer’s friend, the painter F. Hopkinson Smith.

Weary, I think, of the unrelenting brokenness of American life, Homer took a short residency in the north coast of England in 1881. He would end up staying 19 months, transfixed by the hardscrabble life of the working-class people who clung to that unforgiving shore for dear life. His time there infused his work with a powerful sense of mortality, yielding both paintings of high drama that could occasionally border on kitsch — “The Life Line,” 1884, is a bit much, bodies skimming the white froth of an angry sea — and somber scenes of simmering terror. “To the Rescue,” 1886, captures a figure loping up a sandy shore while black clouds knot and cluster overhead, foreshadowing a nightmare.

Something crystallized there: Homer, afflicted by the binary of North and South, slavery and abolition, saw a larger world of empire with disparities that transcended the American condition. It would leave him attuned to widening inequity. (A small but potent little watercolor, “The Life Brigade,” 1882, is stuck in my head; it shows rescuers huddled in the dark of a boathouse, a wall of furious sea waiting just beyond drawn doors.)

Homer would carry this perspective to the Bahamas, Cuba, and Bermuda in 1884 and 1885, as his work became more explicitly about division and control. “A Garden in Nassau,” 1885, depicts a young Black boy outside the wall of a lush private estate; “The Bather,” 1899, is a watercolor of a Black man chest-deep in the ocean while a Union Jack flies overhead.

“Crosscurrents” explains that Homer’s Caribbean watercolors were dismissed next to his large-scale oil paintings. But there’s nothing minor about Homer’s watercolors, here or anywhere, something he knew well enough himself. “You will see in the future,” he wrote, “I will live by my watercolors.”

The show casts itself as a recovery effort for these works, dovetailing them with the whole of his career. The Caribbean watercolors, I thought, brought Homer back to his roots. Loose and immediate, they feel like eyewitness reportage: dispatches from the frontlines of a world unraveling.

Landing finally at “The Gulf Stream,” now up close, you find a discordant crescendo. Is it really what Homer was building up to? It’s a blustery picture, bald-faced and explicit, the heavy oils of its palette shading from black to sun-bleached, bottom to top. There’s no ambiguity to the fearless grimace of its lone human subject, nor the extremity of threat he faces. Sugar cane, a source of colonial wealth, curls at his feet. Within the energetic watercolors all around, Homer had shaded subtly from enigma to threat.

“The Gulf Stream,” is striking, pointed, and threatens to blow it all away. It comes at you all at once — Imperialism! Domination! Danger! — an overwhelming emblem of colonial malevolence. It also makes a point crucial to Homer’s life’s work, exposing the folly of human enterprise and its flyspeck significance in the face of indifferent planetary churn.

“Crosscurrents” might have ended there, a fine point, and I wonder if it diluted its purpose with its lingering denouement of wildlife scenes and mountaineering. But let’s connect the dots. Importantly amid the end chapter are those great big scenes of thundering seas exploding on the rocks at Prouts Neck — “Northeaster,” 1895, reworked 1901; “Driftwood,” 1909, the year before he died — Homer alone, in the grip of forces far beyond his control.

I’ve always thought of his final years there as a surrender, or a retreat, abandoning our little scurrying species for a view of the elemental, the eternal, the unstoppable. “The Gulf Stream” is that, too, a portrait of hubris and vulnerability, the futility of trying to direct what we simply cannot. Homer was a man of his time, saw it clearly, and committed it to paint. Above all, he knew that time was fleeting, destined to vanish beneath the waves.

At Metropolitan Museum of Art, 1000 5th Ave., New York. Through July 31. www.metmuseum.org, 212-535-7710.

Murray Whyte can be reached at murray.whyte@globe.com. Follow him on Twitter @TheMurrayWhyte.

Work at Boston Globe Media