Actor James Arness is shown in this undated photograph provided by the Arness family.[Photo/Agencies]

Actor James Arness, who personified the tall, rugged lawman of the American frontier as Marshal Matt Dillon on "Gunsmoke," U.S. television's longest-running prime-time drama, died on Friday at age 88.

Arness died of natural causes at his Los Angeles home, said his business manager, Ginny Fazer.

The actor was in relatively good health but had "just been fading" in recent years, Fazer told Reuters. "No disease, nothing untoward, he just got tired, I guess," she said.

Arness was best known for his 20 years on TV playing Matt Dillon, the U.S. marshal in the dusty wild-west town of Dodge City, Kansas, a role for which he was recommended by his showbiz mentor and friend, the film star John Wayne.

When "Gunsmoke" left the CBS airwaves in 1975, Arness had set the record for the longest-running role played by a single actor in prime time. The feat that went unmatched until Kelsey Grammer tied the record after 20 years of playing psychiatrist Frasier Crane on two NBC comedies -- "Cheers" and "Frasier."

"James Arness will always be remembered as one of the biggest stars in the history of television, playing an iconic role on the medium's longest-running prime-time drama ever," CBS said in a statement.

"Gunsmoke," which originated on CBS radio in 1952 with William Conrad as the voice of Matt Dillon, debuted on TV as one of the first in a wave of "adult westerns" that sought to portray gunslingers and cowboys in a way that appealed to grown-up viewers, rather than youngsters.

Although not an immediate hit, "Gunsmoke" climbed up the ratings chart to No. 8 in its second season and went on to become the top-rated show on U.S. television from 1957 to 1961.

The show's success helped generate a lot of competition, with network television's prime-time lineup including more than 30 westerns at one point, but "Gunsmoke" outlasted them all.

MEMORABLE ENSEMBLE CAST

The cast comprised one of television's most memorable ensembles of supporting characters -- the good-natured but gullible deputy with a limp, Chester Goode, played by Dennis Weaver; the red-haired, whiskey-voiced saloon keeper Miss Kitty Russell; crusty old "Doc" Adams, and Louie, the town drunk.

Chester, who spoke with a pronounced twang -- "Meester Deellon!" -- left the series in 1964 and was replaced by scruffy deputy Festus Haggen. Miss Hannah took over the Long Branch Saloon after Kitty's exit.

Arness, who stood 6-feet-7-inches tall, earned three Emmy nominations for the program over the years.

Born James Aurness in Minneapolis to a family of Norwegian heritage, Arness dropped the "u" at the outset of his film career. He attributed his acting success to luck.

He was severely wounded in the leg in World War Two, which left him with a life-long limp.

While recuperating, his younger brother Peter -- who gained fame as the actor Peter Graves in TV's "Mission: Impossible" -- encouraged him to take a radio course. Arness got an announcing job, but then headed to Hollywood in hopes of a movie career.

He made his film debut in "The Farmer's Daughter" in 1947 as Loretta Young's brother, and appeared four years later in the title part as a space alien in "The Thing from Another World."

An agent who represented John Wayne later introduced him to Arness, and Wayne took the actor under his wing, giving him roles in several of his movies. Wayne ultimately suggested Arness for the lead part in "Gunsmoke," and even introduced the first episode for CBS.

Arness returned as Matt Dillon in five "Gunsmoke" reunion specials, the last of which aired in 1994 when he was 71. He also starred in the 1977 TV mini-series "How the West Was Won," the modern police drama "McClain's Law" in 1981, and reprised John Wayne's role in a TV remake of "Red River" in 1988.

Arness is survived by his second wife, Janet, two sons and six grandchildren.