By the mid-1970s, Westerns had largely ridden off into the sunset on network television. When Matt Dillon hung up his gun belt in March of 1975, it marked the end of an era for a format that once seemed bulletproof. Fittingly, it would be James Arness — Gunsmoke’s Marshal Dillon himself — who helped kick off the next stage of the genre’s evolution on TV.

In January of 1976, Arness starred in The Macahans, the pilot film for what would become How The West Was Won. Over the next three years, the series loosely based on the 1962 MGM film would air annually in short “seasons” that lasted between three and fourteen weeks. Each episode was double length, so they felt more like chapters in a continuing saga than the self-contained Western dramas and action shows of the 1950s and 60s. In that sense, How The West Was Won was an early example of the lavish, big-budget Western mini-series and telefilms that would follow in the decades to come. It was part mini-series and part movie — and all entertaining.

You can see what we mean when this rarely rerun classic joins the getTV lineup this month. How The West Was Won airs Sundays at 12:30p ET as part of our expanded “Sundays Under the Big Sky” lineup of classic Westerns.

While the film weaves together multiple narratives unfolding over half a century, the TV version focuses on one family at a tumultuous moment in American history. With the Civil War on the horizon, rough-hewn mountain man Zebulon Macahan (Arness) returns home to Bull Run, Virginia to get his family out of the war’s path. His brother Tim (Richard Kiley) and nephew Luke (Bruce Boxleitner) are unwillingly conscripted into the Union Army as they head West, with tragic results. Tim’s wife Kate (Eva Marie Saint) homesteads in Nebraska with the children — teenagers Jed (William Kirby Cullen) and Laura (Kathryn Holcomb) and younger daughter Jessie (Vicki Schreck) — until it’s safe to continue the trek. And Kate’s sister Molly Culhane (Fionnula Flanagan) joins the family as they journey across country and eventually settle in Wyoming.

Like the film version of How The West Was Won, the TV series includes delightfully poetic narration. Classic TV fans will recognize the unforgettable voice of William Conrad, narrator of The Fugitive and Rocky & Bullwinkle and star of Cannon and Jake And The Fatman. Conrad and Arness had a long history — and had played the same role at the same time for more than five years. Conrad originated the character of Matt Dillon on radio in 1952 and continued playing him until 1961, while the handsome, 6-foot 7-inch Arness took on the part when the TV version launched in 1955.  

“I loved the character because he was the complete opposite of Matt Dillon,” Arness told the Television Academy Foundation in 2002. “This guy was a wild mountain man who lived strictly by his own laws.”

As the star of the longest-running scripted drama series in primetime history, Arness knew how to deliver dialogue. But it helped that How The West Was Won creator Jim Byrnes had also been a Gunsmoke writer for seven seasons and knew Arness’ strengths. Byrnes penned 34 Gunsmoke episodes between 1968 and 1975 and had the good sense to bring along other writers who had as well. Of the fourteen credited writers on How The West Was Won, eleven had been scribes for Gunsmoke.

Byrnes’ partner on How The West Was Won was writer/producer Albert S. Ruddy, co-creator of the World War II-set sitcom Hogan’s Heroes. Ruddy also went on to create the contemporary Western action series Walker, Texas Ranger two decades later. Byrnes also wrote for Walker, which shares more than two dozen actors with How The West Was Won (including Noble Willingham.)

While the behind-the-scenes talent is top-notch, How The West Was Won’s greatest strength is its cast. Eva Marie Saint was an Oscar winner for On The Waterfront who had started on TV, with Emmy-nominated performances on Golden Age series like The Philco Television Playhouse. Kiley got his start on the Broadway stage, with Tony wins for Redhead and Man Of La Mancha. Irish actress Fionnula Flanagan had just won an Emmy for ABC’s Rich Man, Poor Man when she took over for Saint beginning in season two. And 25-year-old Boxleitner — who had also appeared on Gunsmoke — scored his big break on How The West Was Won thanks to Arness, who lobbied for him when ABC network chief Michael Eisner wanted another actor.   

“Bruce turned out to be a great choice,” Arness told the TV Academy. “He was just right for it.”

Saint and Flanagan both scored Emmy nominations, as did Ricardo Montalban as Satangkai, a Native American warrior. And the guest star ranks are filled with some of the best character actors of the era, including Western icons Jack Elam, Iron Eyes Cody, Dub Taylor, L.Q. Jones, and Ken Curtis (another Gunsmoke alum).

Sadly, what makes How The West Was Won so unique today was a contributing factor to its premature demise. The feature-length episodes were “a tremendous physical workload,” Arness said. He had to leave the series in 1979 to have surgery on a “bum leg” that was exacerbated by the extensive location shooting.

“They were ready to go on for several more seasons,” he said.

Arness and Boxleitner would reunite 15 years later for the TV icon’s final performance: a 1994 reunion movie of Gunsmoke.

How The West Was Won airs Sundays at 12:30p ET. For more, visit the getTV schedule.