The general rule with Margo Martindale’s (top) characters in recent years is to become wary when she seems to get all nice.

That was true in Justified, it’s true in The Americans, and now it’s true again in Sneaky Pete, a new Amazon series that premieres Friday.

Martindale plays Audrey, the matriarch of a family that runs a struggling bail bond business. The family’s life is changed, and many of its dark secrets surface after Pete (Giovanni Ribisi, below with Martindale) shows up pretending to be their long-lost nephew.

Like Maggs Bennett from Justified, says Martindale, Audrey above all wants to protect her family, even when that means bending a few rules.

“Audrey’s intuitive,” says Martindale. “She’s really smart. She can step into difficult jobs and get them done.

“It’s possible she can also get in over her head.”

A flashpoint scene for Audrey comes early in the series when a connected thug named Abraham Persikof (Domenick Lombardozzi) skips out on the bail that Audrey’s company has put up.

Abraham’s mother smugly explains why she can’t tell Audrey where Abraham is and essentially says there’s nothing Audrey can do about it.

Audrey smiles politely then methodically explains why Mom will give Abraham up and the bad things that will happen if she doesn’t.

“You get a little glimpse into Audrey’s past from how she levels that woman,” says Martindale. “How she became who she is. What’s also interesting about that scene is Pete’s reaction. He’s thinking, ‘Whoa! She’s a lot more than I thought.’“

Martindale admits, however, that Audrey may be a little different than Martindale herself had been thinking.

“I had a whole backstory for her that I was working on,” Martindale says, in a tone of wry humor. “I told [showrunner] Graham Yost and he said, no, you can’t have all that because some of it doesn’t all fit with where the character is going.

“So I’ll use their backstory. But I have to admit, I still like mine, too. Maybe I’ll put it out later.”

Part of the issue there, Martindale acknowledges, is that no one knows for sure exactly where Sneaky Pete will go.  

“The writers see something they can latch onto and they may take a character in a whole new direction,” she says. “Serial television is very different from a movie or a play. There’s a beginning, but there’s no end. It’s alive, and when it’s good, like this show or The Americans, you hope it just keeps going on.

“That’s one reason television is a fabulous medium.”

Sneaky Pete has a dark premise and, accordingly, takes dark turns. Pete, a small-time con man whose only emotional connection in the world is to a single brother, wants to embed himself with Audrey’s family because otherwise a nasty man named Vince, played by Bryan Cranston (right), would have already killed him. (Cranston is also a co-creator of the show.)

Audrey’s family, meanwhile, is hardly the Brady Bunch, and adding Pete ensures that its dysfunction will reach new heights.

For all that, however, says Martindale, it’s important that many of these characters on some level be sympathetic.

“Pete has to be a likable person,” she says. “He’s also a complicated person. There’s something he’s looking for in life, and maybe he’s found it in this family. Or maybe he hasn’t.

“The audience has to also believe that what matters most for Audrey is keeping the family together. There are other things going on, but she never loses sight of that.”

Along the way, Martindale adds, Sneaky Pete needs some lighter touches.

“As a viewer, I need humor in everything I watch,” she says. “If it’s all dark, I can’t be brought into it.”

Speaking of humor, Martindale did take one notable character detour a couple of seasons ago when she starred in the relatively short-lived CBS sitcom The Millers.

She played a matriarch there, too. Just a zany and goofy one.

“I had always wanted to do a sitcom,” she says. “And at the time my contract with The Americans had expired, so I was looking for a show. That job came up, so I took it.

“I learned a lot from doing it, and it was something I had to try. That being said, I’m very happy to be back on The Americans and Sneaky Pete.”

The Americans has two more seasons left, this year and 2018, and Martindale says she has no inside information on what will happen to the embedded Soviet spies at the heart of the story.

“I don’t know what’s planned,” she says. “Personally, I don’t want them to get caught. I’d like them to blend into America.”

Martindale, who just turned 65 and has had no trouble staying busy the last few years, says she has no intention of retiring herself – especially now that she’s reached the point where she doesn’t even have to audition for roles anymore.  

“That’s nice,” she says. “You don’t spend a lot of time preparing for something you won’t ever get the chance to do – which is what most actors have to do.”

Living in New York, she says she might even return to the stage.

“I’ve done a lot of plays over the years,” she says, though none since Cat on a Hot Tin Roof in 2004. “It can be difficult. You give your life away when you sign on to do a play. But if the right one came along, I would.”