Nancy Dubuc is a producer at heart. It shows every time she’s in a pitch meeting.

“Nancy loves being a programmer,” says Leslie Greif, a producer who has fielded numerous shows for A&E Networks, most recently History’s record-setting miniseries “Hatfields & McCoys.”

“She always makes sure that everybody understands the definition of what’s going to make the viewer enjoy this particular show. She’s not coming from that lawyer/accountant/MBA clinician approach to TV. She comes from producing. She comes at every project saying ‘What makes good TV?’ ” Greif says.

Dubuc, prexy-g.m. of Lifetime Networks and History, became one of the cable biz’s most prominent programming execs after steering a remarkable transformation at History. She was part of the team, with Abbe Raven and Bob DeBitetto, that reinvented A+E Networks nearly a decade ago and her flair with original programming earned her a promotion two years ago to running Lifetime in addition to History.

The evolution of History is a cable case study in how to turn a good business into a robust profit center with savvy programming and marketing.

History was once known for fighting WWII every day; today it’s the home of “Pawn Stars,” “Swamp People,” “Ax Men,” “American Pickers” and “Ice Road Truckers.”

The key to the makeover that Dubuc and her team implemented at History in 2007 was opening their minds to the potential for the channel to expand its aud, and draw viewers younger than the Greatest Generation.

“It was less about coming up with a specific programming mantra and more about asking ourselves, ‘Why not? Why can’t you do that on History? ‘ ” Dubuc says. “It was really a process of giving ourselves the freedom to push the limits and to trust that the audience will be the constituency to tell us when we’ve gone too far.”

Dubuc and her lieutenants — including Dirk Hoogstra, David McKillop and Rob Sharenow — studied History’s history for guidance on how to chart the course for its future.

Execs noticed that the long-running docu series “Modern Marvels” always performed well when the episodes were about ordinary people doing extraordinary things. One seg in particular, on the truck drivers who specialize in traversing dangerous icy roads, always drew a crowd. That inspired Dubuc to reach out to Thom Beers, the producer behind Discovery Channel’s “Deadliest Catch,” to deliver “Ice Road Truckers.”

“That show jolted the creative community to think about the possibilities of our brand,” she says. ” ‘Hatfields & McCoys’ is another example of challenging the creative community. When people come to pitch us, we tell them, ‘Don’t bring us what you think we want, bring us the best shows you’ve got.’ Don’t be our editor. That’s our job.”

For sure, there was a vocal minority that complained loudly about the thrust of the new programming. There was more outrage when they decided to drop Channel from History’s formal moniker, and still more when they revamped History’s on-air logo to remove the boxy border around the big yellow H. “That seemed to wind people up more than anything else,” Dubuc laughs.

But the Nielsen numbers had the final say. Since Dubuc took the reins, History has vaulted from No. 17 among basic cablers in the 18-49 demo to No. 5, and from No. 11 to No. 2 in adults 25-54. The cabler has logged two consecutive years of demo gains of more than 50% — an eye-popping performance that no other established network can match. That growth has allowed A+E Networks to invest more in spinoff H2, Dubuc notes, which carries more of the longform docus that used to run on the mothership.

“We’re in the business of ‘best year ever’ around here,” Dubuc says. “The expectation is that you’re going to continue to expand your audience horizons and your ad sales horizons.”

The “Hatfields” mini is a good example of Dubuc’s determination, Greif says. Although the event-miniseries has fallen out of fashion for every network but HBO, she was convinced there was an audience for an epic tale of Americana spread over three nights.

Moreover, Dubuc championed the Kevin Costner-Bill Paxton project even after suffering a very public blow with “The Kennedys.” History’s first scripted miniseries was felled by corporate intrigue (the subject matter became radioactive to A+E Networks parent Disney) and political controversy just weeks before the mini was to premiere in spring 2011.

Dubuc credits her ability to move quickly and decisively to her early years in TV news.

“You learn very quickly in news that every day is a new day. It’s an important thing to remember in this business from the standpoint of fostering creative work,” Dubuc says. “I also learned that it’s never too late to make a change if something is not working.”

Dubuc by nature is competitive and athletic. Growing up in Rhode Island, she was a member of the crew team at her all-girls high school. These days, as the mother of a young boy and girl, her pursuits lean more toward Scrabble and “Angry Birds.” She’s also a foodie who enjoys dining out as much as cooking in her own Manhattan kitchen.

After graduating from Boston U. in 1991, Dubuc got her start in TV as producer and production coordinator, first for the Christian Science Monitor and then Boston pubcaster WGBH.

She was supervising producer for the Discovery Channel newsmag “Discover” in 1999 when she met Raven, who was then head of programming for History. Raven recruited Dubuc to spearhead a magazine show for History. Dubuc joined the cabler’s staff, and Raven quickly recognized her potential as a leader.

“I didn’t really want to be a cable programming executive but here I am,” Dubuc says. “All I ever wanted to do was produce great shows.”

With Lifetime added to her canvas, Dubuc has no shortage of opportunities to pluck needles from haystacks. She came in with a mandate to shift the cabler more deeply into the original programming business — the channel will have 300 more hours of originals this year than in 2011.

In the competitive arena for female-focused programs, Dubuc sees Lifetime’s advantage as being the “triple threat” that offers original scripted series and telefilms as well as unscripted shows.

Lifetime scored earlier this year with the telefilm-turned-series “The Client List,” starring Jennifer Love Hewitt as a struggling mother who turns to prostitution. Dubuc also made a bold move in giving a series order to a Latina-themed sudser from “Desperate Housewives” creator Mark Cherry that was originally produced for ABC. “Devious Maids” will be a big bet for the new regime — and an effort to bring more Hispanic viewers to the channel — when it bows next year.

Dubuc is a firm believer that the bottom line for any network comes down to the quality and distinctiveness of its shows. She sees her primary job as to set the tone and provide support, just as Raven has done for her over the years.

“The only formula that works is to nurture a creative environment, hire the right (people) and give them the freedom to do what they do best,” she says. “My job is to encourage them at all costs and create an environment that embraces creative risk.”