For all of its gut-wrenching drama, powerful acting and stunning depictions of unspeakable brutality but also chill-inducing moments of humanity in the South during and after the Civil War, for all of its reminders of where we’ve come from, how far we’ve come and yet how far we have to go, “Free State of Jones” is a film destined for vocal blowback.

It’s a film about slavery and Reconstruction, set in Mississippi in the 1860s and 1870s — but a white man is front and center as the hero of the story. When Matthew McConaughey’s Newton Knight explains to a bigoted white man that all poor Southerners are essentially the n-word (and he uses the n-word), when he leads two dozen armed, singing black men into town in 1875 so they can cast ballots for the first time, it smacks of the “Crusading Caucasian” syndrome.

As author and history professor Kellie Carter Jackson says in an article in the New York Times, “If [the story] is really about Knight being an ally, then shouldn’t McConaughey be the supporting actor and not the lead?”

Also expect to hear criticism of the film’s somewhat sanitized depiction of Newton Knight as a charismatic, noble superhero of civil rights, with speechmaking abilities to rival Lincoln’s, and the unwavering compassion of a saint. (In what might be a first for a historical biopic, “Free State of Jones” comes with its own heavily annotated website, on which director Gary Ross footnotes some 35 scenes and topics of discussion from the movie.)

The truth, as is almost always the case with fictionalized biopics of historical figures, is much more complex. (Update Newton’s COMPLETE family history to modern times, and I’m not sure even the most salacious producer would turn it into a reality show. To say he and his descendants kept it all in the family would be a huge understatement.)

It would seem irresponsible to address an important film that focuses on race — the dominant issue in the history of this nation — without noting the aforementioned concerns, but our primary purpose here is to review the film Gary Ross has made, and not the film others might wish he had made. And while “Free State of Jones” is indeed a movie about slavery and race with a white man as the leading hero, and while it most certainly, shall we say, “streamlines” that man’s personal life, it is primarily an immensely gripping tale rooted in historical fact and filled with unforgettable images and, yes, lessons that ring hard and true a century and a half later.

As glossy and polished as McConaughey looks in those ubiquitous luxury vehicle ads, as ridiculous as he sometimes came across during his “Shirtless Romantic Comedy Role” lost years, we know he also won’t hesitate to strip away all vestiges of vanity when the role calls for it. (The obvious example being his Oscar-winning turn in “Dallas Buyer’s Club.”)

As Newton, a farmer turned Confederate medical nurse turned deserter turned leader of a rebellion, McConaughey loses himself in a bushy beard, mud- and blood-speckled face, historically accurate discolored and uneven teeth, and a mop of hair drenched in sweat and grime.

More important is the work he delivers. It’s pure and true — a raw and honest performance. Even when McConaughey’s Newton is clinging tight to a woman he loves or igniting a crowd to action, there’s never a hint of his famous twinkle or his look-at-how-great-I-am grin or his stoner drawl. We believe this movie star as a swamp-soaked Mississippi outlaw-crusader.

“Free State of Jones” begins in 1862, with the Civil War in full bloody bore. (Ross’ camera doesn’t shy away from excruciating close-ups of spilled innards, severed limbs and faces turned into horror shows by gaping wounds.)

Already steaming about a new law exempting Confederate sons from military service depending on the number of slaves the family owns (for every 20 slaves, another son is sent home), Newton reaches the breaking point when his beloved young nephew lasts but a few hours in combat before a Union sniper takes the boy out.

Newton is taking his kin home. It’s as simple as that for him. Of course, that’s also known as desertion, and once Newton is back on his home turf in Mississippi, it’s a matter of time before Confederate soldiers are hunting him down with the same dogs they use to track runaway slaves.

Wanted for treason and depending on the kindness (and yes, the sometimes nearly magical powers) of sympathetic slaves, Newton holes up deep in the bayou with a small band of runaways, including Moses (Mahershala Ali), who retains his dignity and resolve even with a heavy, spiked metal collar still bolted to his neck.

Writer-director Ross provides helpful subtitles and historical updates as the story progresses. (Occasionally we jump ahead some 65 years, for a trial involving one of Newton’s descendants.)

Newton’s wife Serena (Keri Russell) is out of the picture, having fled to Georgia with their infant son. As Newton’s company of runaway slaves and Confederate deserters grows to 100, then 200 and more, he finds love with Rachel (Gugu Mbatha-Raw), who somehow manages to make her way to the bayou with food and other provisions on a regular basis, even though she’s still the property of the evil plantation owner James Eakins (Joe Chrest).

Week by week, month by month, Newton and his ragtag band outwit and outgun the Confederates, taking over a considerable portion of southeast Mississippi. (Newton declares his home county “The Free State of Jones.”)

At times the speechifying in “Free State” stretches credulity. Is it possible Newton was even remotely this articulate? And even though it’s true Newton’s wife and son returned to Mississippi and wound up living on the same property with Newton and Rachel, a scene where Serena and Rachel share a moment on the front porch comes across as highly idealized.

The terrific character actor Thomas Francis Murphy (“12 Years a Slave,” “Focus,” “Self/Less”) brings a Donald Sutherland-esque, casually slithery villainous touch to the role of the Confederate commander who counters Newton’s rebellion by hanging children and burning down farms.

Ali’s portrayal of Moses is strong and memorable. Mbatha-Raw gives a wonderful performance as the strongest female character and the true heart of the story.

This is no history lesson, but it’s mainstream Hollywood entertainment that respects the history and seems to invite discussion and debate.

★★★1⁄2

STX Entertainment presents a film written and directed by Gary Ross. Running time: 139 minutes. Rated R (for brutal battle scenes and disturbing graphic images). Opens Friday at local theaters.