Emily Berl/The New York TimesCasey Wilson, the co-star of “Marry Me,” with David Caspe, the NBC sitcom’s creator — and also her husband — at their home.

LOS ANGELES — Last year, a few weeks after ABC canceled “Happy Endings,” a sitcom with a cult following but weak ratings, its creator, David Caspe, needed a new premise. Pitching season was beginning, and this would be a chance to get another show on the air. He looked no further than a “Happy Endings” cast member, Casey Wilson, at the time his girlfriend and now his wife, and the path it took to merge their lives.

“I am a lower-key guy,” said Caspe, 35, who also thinks of himself as fastidious, quiet and an avoider of confrontation. Wilson, on the other hand, is messy, an unfiltered talker who is as quick to fly off the handle as she is to switch gears into a sunny mood.

“We’ve had our struggles,” said Wilson, 33, as she and Caspe ate lunch in his windowless “Marry Me” office at Paramount Pictures. “I once told him in a fit of rage that I wanted to drive my car through his new house,” she said. “Then five minutes later, he saw me eating gummy bears and laughing at the TV. I think those emotional swings have been a lot for David to process.”

The bearded, slightly rumpled Caspe nodded his head in agreement. “She’s insane,” he said.

With his opposites-attract conceit in place, Caspe made the rounds at the networks, sketching out episodes, characters and comic possibilities for the new show. He also hit upon a unique selling tool he couldn’t disclose to Wilson.

“I was openly telling all these rooms of executives that I was going to propose to Casey, but she didn’t know yet, and that Season 1, I would be living it as I’m writing it,” he recalled. “Technically, all the presidents of all of the networks knew I was going to propose to Casey before Casey or anyone else did. Then I’d swear everyone to secrecy.”

In the end, the network brass — including that of NBC, which bought the concept — kept mum. But apparently Wilson wasn’t completely in the dark.

“I thought it was some big surprise,” Caspe said of the evening he popped the question. “But she showed up in full hair and makeup. She totally knew what was happening.”

In the pilot episode of “Marry Me,” which begins Tuesday, the couple at the heart of the series — mild-mannered Jake (Ken Marino) and Annie (Wilson), the emotionally chaotic woman he loves — stumble through a nightmare version of the evening that Caspe asked for Wilson’s hand. Yet in Caspe’s view, “the title is misleading,” he said. “It’s not like Episode 1 is the proposal, Episode 2 is trying to get the dress. It’s really just a show about a couple, their friends and their family.”

That said, Wilson was willing to share one plot turn.

“Spoiler alert,” she said. “There will be a wedding at the end of the first season.”

Then again, the season finales of “Happy Endings” — which, like “Marry Me,” had a sprawling ensemble cast and featured sharply written dialogue filled with pop culture references and insults, delivered at extremely high speeds — were known to end with weddings, too.

Although “Happy Endings” had a steadfastly loyal following, part of the couple’s self-deprecating banter involves jokes about how few viewers tuned into the series. When the show was canceled, Wilson said, “the three people that were watching were so upset, and one was suicidal.”

Wilson, who studied drama at the Tisch School of the Arts at New York University, has a filmography that suggests that she works constantly: She has a small but showy role as a loudmouth neighbor in “Gone Girl” and appears on Hulu’s “Real Housewives” sendup, “The Hotwives of Orlando.” She wrote and starred in (with her writing and performing partner of 12 years, June Diane Raphael) a 2013 indie film called “Ass Backwards.” She and Raphael, both Upright Citizens Brigade mainstays, also wrote (with Greg DePaul) the 2009 Anne Hathaway studio comedy, “Bride Wars.” And Wilson did a stint on “Saturday Night Live” (albeit a short one).

Just outside Caspe’s office sits a huge dry-erase board dense with story ideas. Embedded in the swarm of scribbles is the outline for a future episode inspired by a true event: Last year, Wilson’s father, political strategist Paul Wilson, got engaged at the same time as both Wilson and her younger brother, Fletcher Wilson, a medical technology entrepreneur.

Then she recalled an anecdote, one she had shared with the writing staff, about buying a box of weight-loss shakes from a neighbor and finding herself inserted into a shifty-sounding sales strategy.

“I could see the glint in their eyes when I told the writers how suddenly within two hours of buying these shakes, I’d been called by this top person, I’d given them my social, and they were trying to get me to Facebook about it,” Wilson said. “And they were all like, ‘You did what?’”

“We turned that into an episode about a pyramid scheme,” Caspe said.

“You did?” Wilson said, her eyes widening in surprise.

Caspe smiled at his wife.

“I’ve said this about Casey before, but I’d love to just put a camera on her and just watch her bounce off the walls of this world.”