Actor Michael Ealy was in the midst of renovating his own home when a script came his way about a man who sells his house to a young couple, but then, at first mysteriously but later ominously, refuses to leave them be after turning over the keys.

“I understand this whole idea of the American dream and buying your first house, starting your family,” Ealy said, comparing real life with his new film “The Intruder.” “It was timely for me, and that was enough for me to be [say] yeah, I’m in.”

In “The Intruder,” which opens Friday, Ealy (“Being Mary Jane,” “The Following”) and Meaghan Good are Scott and Annie, a San Francisco couple who decide to buy a home in nearby Napa County from Charlie (Dennis Quaid), who parts with the home reluctantly, and then continues to find ways to return to his home and insert himself into the couple’s lives—beginning by showing up one day, unbidden, to mow their lawn.

“Have you ever seen him like this?” Ealy said with a smile of his co-star Quaid, whose joker grin and charm from such earlier films as “The Big Easy” are turned upside down to sinister effect in “The Intruder.” “He definitely has this way about him that makes you fall in love with him. But at the same time, he slowly but surely goes to a place of darkness and is totally believable and terrifying. And I think he nailed it.”

“The Intruder” tantalizes the viewer into thinking that perhaps there may be a supernatural element or reasoning behind Charlie’s twisted attachment to his former residence. However, it was that precise lack of a magical element that drew Ealy to the project.

“What I liked was the smallness of it. I loved the simplicity of the story and how it wasn’t rooted in anything supernatural or anything that required special effects,” Ealy said. “Nobody has superpowers. There’s no lasers or anything.”

“The original script [was] a small and sweet story that turns bad. This beautiful couple just falls into something awful.”

At one point in the film, Charlie shows up at the couple’s door wearing a bright-red baseball cap and carrying a shotgun. The red hat perhaps might make the viewer think of a certain president’s signature apparel item, but Ealy will say only that’s a question for the film’s director, Deon Taylor.

“I was told that was Dennis’s choice. That’s the extent of what I know,” Ealy said with a slight chuckle.

He added that although he and Good are black and Quaid is white, the script made no indications as to the skin colors of any of the characters. The races of the young couple and Charlie could have been reversed—or all three could have been of the same race—and had the same effect, Ealy said.

Ealy, who grew up in the D.C. suburb of Silver Spring, Maryland, went to New York to study acting after graduating from the University of Maryland. His influences included Denzel Washington, Sean Penn, Don Cheadle and Tom Hanks.

On an early film of his, 2002’s “Bad Company,” he had a quick scene with Anthony Hopkins. Impressed with the younger actor’s talents, Hopkins told Ealy to then call him “Tony.”

“The goal is to bring your A-game and be ready to work,” Ealy said of his trade. “Yes, Dennis [Quaid] was a part of why I wanted to sign on [but] there’s no such thing as fear or intimidation when working with someone like that. Because I’m thinking maybe I can learn something.”

Ealy says he advises young actors now to go to New York to learn theatre if they are serious about making a stab at the acting game. During his time in D.C., Ealy also gave a talk at Howard University, and advised would-be actors and filmmakers to learn the business side of entertainment as well as the creative end.

“That is a huge part of it now. A huge part of it. I really wish I could somehow create some conservatory, whether it’s at NYU or some local school in Manhattan, to start teaching the business side,” he said.

Another reason Ealy signed on to “The Intruder” was that his character, Scott, wants to start a family. Ealy, forty-five, has young children of his own, and describes fatherhood as “the hardest job you’ll ever love.”

“As much as I wish I could have had kids in my twenties, because I would have had more energy, I would have been a terrible father,” he said. “I tell this to anyone who is in their twenties: That’s the time to be as selfish as you want to be and pursue your passion, figure out life.”

“And I remember talking to my mother about it when my son was born, and I think I’m a much better father because I have the patience and I lived before I settled down. I’m happier now.”

That newfound focus on family, he believes, pushed him to make “The Intruder,” what with its portrayal of an American couple trying to build a new life in a new home.

“We were trying to start a family, so it was like let’s go get a house together,” he said of his real-life search for a home with his wife. “The house-hunting thing was always a little daunting to me because you don’t know what’s behind those walls.”

Or who!

“The Intruder” opens nationwide Friday.