Everything Harry Dean Stanton has done in his career, and his life, has brought him to his moment of triumph in “Lucky,” an unassumingly wonderful little film about nothing in particular and everything that’s important. Scripters Logan Sparks and Drago Sumonja wrote their screenplay (a scenario that is arrestingly allusive and rigorously precise, in the manner of an exceptionally well-crafted short story) with Stanton in mind as the title character, and they embellished their handiwork with Stanton-specific biographical detail. Long-time admirers of the iconic character actor would likely embrace this indie dramedy if it were nothing more than a hand-tooled star vehicle for a living legend. But “Lucky” is something a good deal more substantial than the cinematic equivalent of a lifetime achievement award. It’s also a stealthily affecting and unpretentiously thoughtful meditation on community and mortality, and existential dread and transcendence, in the form of a richly amusing shaggy-dog story that features Stanton’s finest performance since “Paris, Texas.”

By turns taciturn and loquacious, Lucky is an insistently self-sufficient loner who nonetheless seems to enjoy — or at least not resent — his interactions with other residents in an off-the-grid desert town. As he goes about his daily regimen both at home (yoga in the morning, TV game shows in the afternoon) and outside of it (breakfast at the local diner, evening drinks at his customary watering hole), his stride is brisk and purposeful in the manner of a man who believes unwavering adherence to routine is the secret to a long life.

And, hey, maybe the guy is on to something: His doctor (a splendid one-scene cameo by Ed Begley Jr.) is amazed by his longevity and, despite his pack-a-day smoking habit, his enduring good health (Stanton was 89 during the 18-day shoot, and Lucky evidently is in the same ballpark). Indeed, there are moments when the character himself appears surprised that he remains alive, ambulatory, and reasonably sentient.

Trouble is, he’s starting to wonder just how long his luck can last.

A resolute and lifelong atheist, Lucky believes that nothing but nothingness awaits him once he shuffles off his mortal coil. But as he edges near that inevitable time, he is ill-prepared to make his leap into the void. Deep down, he’s scared — though, of course, he’d never admit that to anyone. Well, not anyone except Loretta (Yvonne Huff), a waitress from the aforementioned diner, who drops by to check up on him, and sticks around to share her stash so they can get high while watching a rerun of a classic Liberace concert. No, really.

“Lucky” is the first feature directed by veteran actor John Carroll Lynch, and like many others who have made the move to the other side of the camera, Lynch places a greater premium on performances than on plot momentum, allowing almost every member of his cast a chance to strut his or her stuff. Far too often, such an approach leads to lethargic pacing, self-indulgence, and scenes in which dialogue sounds more like monologue. “Lucky,” however, is the exception to the rule.

The characters who revolve in the protagonist’s orbit are so vividly drawn and well played that it’s easy to share Lynch’s desire to spend as much time with them as possible. Sparks and Sumonja have given the supporting players meaty roles, and the actors play them with such unaffected and thoroughly engaging earnestness that you always laugh with, not at, them.

In a different movie made by different people, a scene that calls for one of the townspeople to eloquently express his respect and longing for his missing pet tortoise might have elicited snickers. But David Lynch, of all people, comes across so affectingly and unironically bereft and passionate as Howard, owner of the runaway reptile, that the moment packs a seriously potent emotional punch. Meanwhile, in another corner of the bar, James Darren — yes, that James Darren (aka Moondoggie from the ’50s and ’60s “Gidget” movies, and the younger cop from “T.J. Hooker”) gives what arguably is the finest film performance of his career as Paulie, a putatively reformed ne’er-do-well. Paulie claims he changed his reckless ways decades ago when he hooked up with Elaine (a nicely brassy Beth Grant), owner of the establishment where Lucky regularly raises a glass or two or more. (If the right people see “Lucky,” it could do for Darren what “Jackie Brown” did for Robert Forster.)

Honorable mentions also go to Ron Livingston as an insurance agent who arouses Lucky’s ire before he bares his soul to the old guy; Barry Shabaka Henley as the owner of the favored café; Hugo Armstrong as the bartender who makes a strong case for a quiz show Lucky despises; and Bertila Damas as a grocery store proprietor who inadvertently brings out the best in Lucky. Tom Skerritt also is creditable in his cameo as a World War II vet who conveniently drops by the diner just when Lucky needs inspiration. It’s not his fault that, in a rare lapse of judgement on the part of the filmmakers, he’s burdened with on-the-nose dialogue that’s too obviously inspirational.

The best way to appreciate “Lucky” is to take a deep breath, free your mind, and go with the unhurried flow for 88 minutes. Take time to savor all of its disparate elements — including, on the pitch-perfect soundtrack, a harmonica rendition of “Red River Valley” performed by Stanton — and ponder its teasing ambiguities. More important, relish every detail of Stanton’s matter-of-factly fearless portrayal of a man who ran out of damns to give a long time ago, but still wants to make a graceful exit. It is, quite simply, the performance of a lifetime.