When an actor who’s widely considered to be over the hill comes roaring back with a performance that reminds us of how good he once was, it’s a cause for rejoicing. But when he also sends up his own past persona in the process, the self-aware subtext makes it all the more invigorating. Michael Keaton seemed not long ago to be permanently relegated to secondary roles in junk like “Need for Speed” and the “RoboCop” remake, and to be doing self-parody in them to boot; and when he tried to go beyond the expected range in a good little picture like “The Merry Gentleman” (which he also directed, nicely), the result went virtually unnoticed. But nobody is likely to overlook his ferociously committed turn as the obsessive protagonist in Alejandro G. Inarritu’s “Birdman or (The Unexpected Virtue of Ignorance),” a savage satire of Hollywood celebrity gone to seed and the new Broadway’s reliance on movie stardom to sell tickets that plays on Keaton’s post-“Batman” career vicissitudes, and is delivered with an incredible degree of cinematic panache.

Keaton is Riggan Thomson, who once starred as a screen superhero called Birdman but decided to abandon what could have been a lucrative franchise after a couple installments. His career nosedived, and his marriage collapsed as well. Now he’s trying to recapture the spotlight by starring on the New York stage in his own adaptation of a Raymond Carver story, “What We Talk About When We Talk About Love,” which he’s also directing. During final rehearsals before previews are scheduled to begin, Thomson decides that one of his co-stars is a terrible actor and must be replaced. Before you can say “You’re fired,” the offending guy is conked by a falling spotlight and taken off to the hospital. The accident seems fortuitous, but perhaps it’s the result of the Birdman powers of telekinesis that Thompson seems to have retained, at least in his own mind (at times, when alone, he’ll move objects at will, and even levitate).

In any event, what seems a possible disaster turns into a golden opportunity when Thomson’s co-star Lesley (Naomi Watts) suggests that her boyfriend Mike Shiner (Edward Norton), a major Broadway draw, would be interested in taking over the role. The possibility overjoys Riggan’s pal Jake (Zack Galifianakis, whose understated turn is one of his best), the play’s producer and general factotum. But Shiner, though a guaranteed ticket-seller, proves to be a complete whack job, sending Thomson ever further toward the edge. To make matters even worse, the entire process is being observed by Thomson’s daughter Sam (Emma Stone), just out of rehab and with a considerable chip on her shoulder toward the old man, who’s hardly hiding his relationship with a young co-star (Andrea Riseborough); and Tabitha (Lindsay Duncan) the Times’ all-powerful theatre critic, lets Riggan know before she sees a moment of the play that she intends to bury it with her review.

All of this provides only the barest skeleton of incident in a movie that moves a mile a minute, thanks not only to Keaton’s frantic performance and Inarritu’s white-hot direction, but to Emmanuel Lubezki’s bravura cinematography, which follows Keaton around in what’s calculated to appear like an endless tracking shot, one in which the joints aren’t as obvious as they were in Hitchcock’s “Rope” or the pace as serene as it was in “Russian Ark.” Visually “Birdman” is a virtuoso piece of work, and a viscerally exciting one.

But the script is just as engrossing, filled as it is with inside jokes that won’t pass over the heads of ordinary filmgoers who nowadays devour the trade gossip with as much intensity as industry types have always done. Of course everyone will be familiar with Keaton’s “Batman” past, but that’s but the tip of the iceberg in a screenplay that relishes in dishing up sly references to actors and pictures that make it impossible for the viewer to put their attention on pause mode any more than the on-screen characters can slow down their inevitable march to…well, we’ll leave that for you to discover, and to savor.

On the thespian side, Keaton is of course the major figure here, and he hasn’t been so overwhelming since “Night Shift” and “Beetlejuice.” But Norton matches him beat for beat, making Shiner—the ultimate epitome of the “great actor” for whom every gesture and prop is a matter of life or death—every bit as crazy as Thomson is, in his own, very different way. Galifianakis surprises with a turn that far funnier in its reticence than his more over-the-top starring roles have been, while the distaff side—Watts, Stone, Riseborough, Duncan and Amy Ryan—has less opportunity to shine but does what’s required with ease. Led by Lubezki, the technical crew does aces work as well, with special praise for the antic but not chaotic editing of Douglas Crise and Stephen Mirrione, and the skillful use that production designer Kevin Thompson has made of the St. James Theatre.

One must finally tip one’s hat to Inarritu, who appeared to be trapped by the expectations fostered by the intricately structured “Amores perros,” which gave rise to the similarly-convoluted narratives of “21 Grams,” “Babel” and “Biutiful”—a path that increasingly came to seem an artistic dead end. “Birdman” isn’t really any less complex than those films are, and it’s just as much a stunt; but its artificiality is of another order, and it bustles along with wild abandon while they all remained mired in their ponderous self-seriousness. Inarritu’s cinematic resurrection is no less remarkable than Keaton’s, and “Birdman” represents a triumph for them both.