Rob Reiner has been a Hollywood presence for more than 40 years. (Marvin Joseph/The Washington Post)

Over three decades, his films have included farce (“This is Spinal Tap”), fantasy (“The Princess Bride”), thriller (“Misery”) and courtroom drama (“A Few Good Men”).

But there is also a long line of romance in the two dozen films directed by Rob Reiner, a recurring theme of imperfect coupling leading to a lasting bond.

“I’ve done a few,” Reiner says, easing onto a couch in a Georgetown hotel suite, as rumpled and comfortable-looking as he was when he was an actor on TV’s top show in the ’70s.

“And if you notice, whether it’s ‘Flipped,’ which is about young romance, or ‘The Sure Thing,’ which is about college, or ‘When Harry Met Sally,’ which is adult, and now with seniors, at this stage, in ‘And So it Goes,’ ” he says, “it’s essentially, if you notice, the same story.”

What was once John Cusack and Daphne Zuniga in 1985’s “The Sure Thing” or Billy Crystal and Meg Ryan in 1989’s “When Harry Met Sally” is now late-career Michael Douglas and Diane Keaton in his new film “And So It Goes,” opening July 25.

“It’s like variations of a theme — the Goldberg Variations,” says Reiner, 67.

“It’s my view of men and women,” he says. “And no matter what age they get to, in my mind, men and women [remain] the same.”

Women are more emotionally developed and “are more evolved as people,” Reiner says. “They know what they want in life, and they know what’s important. They have good priorities.”

Men, he goes on, “run around like idiots until they find someone who can make them see what’s important and then they say, ‘Oh, I see.’ ”

Meatheads, you might say.

“And basically, that’s the same story I’ve told over and over,” Reiner says. “I say it in different ways. But it’s this wonderful dance we do, no matter what age we are. And it’s awkward.”

The good thing about doing such a film about retirement-age people — albeit good looking, marquee-ready retirement-age people — is that they’re generally wiser about things, he says.

“As you get older, the things you kind of intellectualize as a younger person you start internalizing,” Reiner says. Young people might think being with family is important, “but as you get older, you know that it’s right,” he says. “You can feel it. So you cherish things more. So hopefully that’s the wrinkle that this story has, because it’s not just about him finding somebody to love at this stage of his life, as it is finding out what’s really important – he’s got this son and this granddaughter and this woman who loves him.”

Speaking of wrinkles, Douglas, who is playing a misanthropic real estate agent in the film, is 69; Keaton, as a neighbor who is an aspiring singer, 68.

They both still have some Hollywood gloss, though.

Douglas, who starred in Reiner’s 1995 “The American President,” “is still a great looking guy, and still has great sexuality and all that,” the director says. “He’s a great guy and a tremendous actor and getting better and better,” evidenced by the role he came directly from, his Emmy-winning turn as Liberace in HBO’s “Behind the Candelabra.”

“And Diane Keaton, who I’d never worked with before and always wanted to,” Reiner says. “I’ve been a huge fan of hers for years.”

Though Keaton and Douglas had both starred in films for more than 40 years, the two had never previously worked together.

Keaton’s distinctive halting style is somehow more suited to an older character than it was when she was an ingénue in Woody Allen films.

Working with her, “There was literally no delineation of who she was on screen and who she was off screen — it’s the same person,” Reiner says. “And I got a tremendous kick out of it because I work in a similar way.”

And, oh yes, that’s Reiner in “And So It Goes” as well, playing Keaton’s schlubby accompanist.

“I was looking for an actor who could work for scale and I basically found myself,” Reiner says. Also: “I jumped at the chance of playing a part where I could wear a hairpiece that was undetectable,” referring to an outrageous rug he wears in the family tradition of Alan Brady — the vain TV star his father, Carl Reiner, portrayed on “The Dick Van Dyke Show.”

As an actor, Reiner still pops up in comic roles here and there, from a parent on TV’s “New Girl” to a short-tempered TV fan in Martin Scorsese’s “The Wolf of Wall Street” who cannot abide interruptions during “The Equalizer.”

“I had fun doing that. That was a great part,” Reiner says of the Scorsese film.

“I like acting,” he says. But generally, he adds, “it’s not as challenging for me as directing, so I would rather do that.”

“And So It Goes” makes no secret that it is trying to attract an audience that is largely forgotten in multiplexes where robots, superheroes and explosions reign.

“Our feeling is there is an audience, clearly, for this kind of thing,” Reiner says. “We’ve seen that with ‘Bucket List,’ ‘Hope Floats,’ and ‘It’s Complicated’ — there is a certain audience. The baby boom audience is still the largest bulge in the population, and if there’s something for them to see, they’ll go see it.

“There’s isn’t a lot for them to see anyway,” Reiner says, “but especially during the summer, unless you want to see somebody blown up, there’s not going to be a movie for you. So we felt there was room for a picture like this.”

A few of his films have become cult classics, from his heavy metal mockumentary “This Is Spinal Tap,” which will mark its 30th anniversary this fall, to “The Princess Bride,” which celebrated its 25th anniversary with a big event at Lincoln Center in 2012.

“It was really thrilling to see people who were 7, 8 years old when they first saw it, and now they’re older and they have kids that age and they’re introducing their kids to the movie, so that was a big kick to me,” Reiner says. “It’s fun to know you’ve made your way into the culture.”

But long before directing his first feature, Reiner had already made his way into the culture as part of the TV hit “All in the Family,” providing prime time with one of the few voices of shaggy haired liberal youth.

Reiner says he didn’t feel the responsibility of a spokesman in the show. “Basically I was espousing my views,” he says. “If anything, Mike was a little bit more liberal than I am,” he says of his character in the Norman Lear comedy. “But it was essentially my point of view, and I was allowed to express it.”

A show like “All in the Family” could work today, Reiner says. “Not on broadcast television, though.”

Sure, the country seems politically divided now. But he adds, “the country was divided then” with Vietnam and other social upheavals.

Reiner has remained a Hollywood activist.

“Recently, we led the effort to overturn Proposition 8 in California, which allowed gays and lesbians to marry,” he says. “And now we’re in the throes of another lawsuit that we filed in Virginia, which is now making its way through the Fourth circuit to the Supreme Court, using the same two lawyers that were in the Prop 8 case, Ted Olson and David Boies.”

From time to time, Reiner has considered running for office as well. But when he brought it up to his family, “My wife and three kids, discussed it, and basically I polled 40 percent of my family,” Reiner says. “So I figured if I can’t carry my family, it’s not a good move on my part.”

Catlin is a freelance writer.

And So it Goes Opening in local theaters on Friday, July 25. Rated PG-13 for some sexual references and drug elements. 94 minutes.