Portis, a former newspaper reporter who apparently learned enough to swear off talking to the media, had been suffering from Alzheimer's in recent years.

Charles Portis was among the most admired authors to nearly vanish from public consciousness in his own lifetime. His fans included Tom Wolfe, Roy Blount Jr. and Larry McMurtry, and he was often compared to Mark Twain for his plainspoken humour and wry perspective. Portis saw the world from the ground up, from bars and shacks and trailer homes, and few spun wilder and funnier stories. In a Portis novel, usually set in the South and south of the border, characters embarked on journeys that took the most unpredictable detours.

In Norwood, an ex-Marine from Texas heads East in a suspicious car to collect a suspicious debt, but winds up on a bus with a circus dwarf, a chicken and a girl he just met. The Dog of the South finds one Ray Midge driving from Arkansas to Honduras in search of his wife, his credit cards and his Ford Torino. In Gringos, an expatriate in Mexico with a taste for order finds himself amid hippies, end-of-the-world cultists and disappearing friends.

The public knew Portis best for True Grit, the quest of Arkansas teen Mattie Ross to avenge her father's murder. The novel was serialised in the Saturday Evening Post in 1968 and was soon adapted (and softened) as a film showcase for John Wayne, who starred as Rooster Cogburn, the drunken, one-eyed marshal Mattie enlists to find the killer. The role brought Wayne his first Academy Award and was revived by the actor, much less successfully, in the sequel Rooster Cogburn.

Rooster was so strong a character that a new generation of film-goers and Oscar voters welcomed him back. In 2010, the Coen brothers worked up a less glossy, more faithful True Grit, featuring Jeff Bridges as Rooster and newcomer Hallie Steinfeld as Mattie. The film received 10 nominations, including best actor for Bridges, and brought new attention to Portis and his novel, which topped the trade paperback list of The New York Times. "No living Southern writer captures the spoken idioms of the South as artfully as Portis does," Mississippi native Donna Tartt wrote in an afterword for a 2005 reissue of the novel.

Portis was born in 1933 in El Dorado, Arkansas, one of four children of a school superintendent and a housewife whom Portis thought could have been a writer herself. As a kid, he loved comic books and movies and the stories he learned from his family. In a brief memoir written for The Atlantic Monthly, he recalled growing up in a community where the ratio was about "two Baptist churches or one Methodist church per gin. It usually took about three gins to support a Presbyterian church, and a community with, say, four before you found enough tepid idolaters to form an Episcopal congregation".

He was a natural raconteur who credited his stint in the Marines with giving him time to read. After leaving the service, he graduated from the University of Arkansas in 1958 with a degree in journalism, and for the next few years was a newspaper man, starting as a night police reporter for the Memphis Commercial Appeal and finishing as London bureau chief for the New York Herald Tribune.

Fellow Tribune staffers included Wolfe, who regarded Portis as "the original laconic cutup" and a fellow rebel against the boundaries of journalism, and Nora Ephron, who would remember her colleague as a sociable man with a reluctance to use a telephone. His interview subjects included Malcolm X and J.D. Salinger, whom Portis encountered on an aeroplane. He was also a first-hand observer of the civil rights movement. In 1963, he covered a riot and the police beating of black people in Birmingham, Alabama. Around the same time, he reported on a Ku Klux Klan meeting, a dullish occasion after which "the grand dragon of Mississippi disappeared grandly into the Southern night, his car engine hitting on about three cylinders".

Anxious to write novels, Portis left the paper in 1964 and from Arkansas completed Norwood, published two years later and adapted for a 1970 movie of the same name starring Glen Campbell and Joe Namath.

Portis placed his stories in familiar territory. He knew his way around Texas and Mexico and worked enough with women stringers from the Ozarks in Arkansas to draw upon them for Mattie's narrative voice in True Grit. He eventually settled in Little Rock, where he reportedly spent years working on a novel that was never released. Gringos, his fifth and last novel, came out in 1991.

Portis published short fiction in The Atlantic during the 1990s, but was mostly forgotten before admiring essays in Esquire and the New York Observer by Ron Rosenbaum were noticed by publishing director Tracy Carns of the Overlook Press, which reissued all of Portis' novels. Some of his journalism, short stories and travel writings were published in the 2012 anthology Escape Velocity.

In recent years, the author lived in open seclusion, a regular around Little Rock who drove a pickup truck, enjoyed an occasional beer and stepped away from reporters. He did turn up to collect The Oxford American's Award for Lifetime Achievement in Southern Literature and was known to answer the occasional letter from a reader. But otherwise Portis seemed to honour Mattie's code in True Grit for how to deal with journalists.