Best known for his clean-shaven, uptight leading roles in Whit Stillman’s trilogy of films about young urban angst among the privileged class (Metropolitan, Barcelona and The Last Days of Disco) as well as Noah Baumbach’s pre-Squid and the Whale work (Kicking and Screaming, Mr. Jealousy), the goateed, relaxed Mr. Eigeman hasn’t spent much time with kids. He only played a dad once on screen, in a small film called Clipping Adam, and isn’t terribly eager to again. (On being offered such parts: “‘Oh, really … the dad?’ I don’t want to play the dad. The dull dad. Or, like, the really mean dad?”) But he has written and directed his first feature film, Turn the River, which will premiere Friday at the Hamptons Film Festival. And making a movie feels, he imagines, about the same as having a baby.

“The affection you have for [the film] has to be the same as the affection you have for one of your kids,” Mr. Eigeman hypothesized, his gray-blue eyes serious, gray-white glinting in his beard. He was certainly dressed for Dad-dom, in loose light blue jeans and a neat white Oxford cloth shirt with a pen in the pocket. “You don’t want to see it manhandled. You don’t want anybody to say anything nasty about it, not even behind your back. When you’re in a film, you have that, but I think to a lesser degree. Here I have very little cover.”

Turn the River is gooey stuff for a guy who’s made his career playing the smartest asshole in the room. It’s the story of a pool-hustling woman named Kailey (played by Mr. Eigeman’s good friend Famke Janssen, the Dutch former model and Jean Grey from the X-Men franchise, whom he met on the set of indie flick The Treatment), who’s trying to win enough money on the table to make a life for herself and her estranged son, Gulley. (Incidentally, Gulley is also the name of the Eigemans’ beloved white German Shepherd, who himself was named after the main character in Mr. Eigeman’s favorite book, The Horse’s Mouth by Joyce Cary. And no, he won’t be naming his actual son Gulley.) In Turn the River, Gulley lives with his dad and stepmother in Manhattan, but sneaks off in secret to meet his mother; the two exchange letters like clandestine lovers via an old friend of Kailey’s.

Perhaps you were expecting that fourth Whit Stillman movie that Whit Stillman hasn’t gotten around to making? Or a Kicking and Screaming for our midlife crises instead of our postgrad rut? Mr. Eigeman’s onscreen persona is so ingrained in the minds of a certain generation (the one currently dominating Brooklyn and East Village streets with banded left hands and baby strollers) that it was hard not to assume that all these years—from his debut as WASP-y Nick Smith in Metropolitan to his turn on Gilmore Girls as a witty, neurotic insurance executive named Digger—we were seeing Chris Eigeman there on the screen, not a character he was hired to portray. He was the crush of choice for every girl who ever, even for a second, dreamed of being Parker Posey.

Sitting in his neatly manicured backyard, Mr. Eigeman is as erudite and quick with a joke as any fan would expect. When this reporter arrived, he was reading The New York Press, wide-eyed over that story about New York Times reporter Deborah Solomon and her questionable interview methods. He dropped references to bands like the National and Arcade Fire as naturally as any 25-year old. He’s hip to the World Wide Web.

But Turn the River reveals a side of Mr. Eigeman that only those close to him know. “Chris is the kind of person who cries really easily, so I wasn’t surprised at all by the sensitivity of Turn the River,” said Mr. Baumbach via phone from the Mill Valley Film Festival in California (lordy, what’s next—a fest on the Moon?), adding that even a political newspaper story can turn his pal misty. Mr. Baumbach, who has remained close to Mr. Eigeman since casting him in Kicking and Screaming more than 10 years ago, shared some of the equipment he used for his upcoming film Margot at the Wedding with Mr. Eigeman, whose movie was made for less than a million dollars and shot around New York City in just 21 days.

Some elements of Turn the River, which takes its name from two poker terms, are straight-up autobiographical—the split-up parents, the gambling and game playing. “My mom and dad got divorced, so it was one of those things where Sundays I’d go to dad’s apartment, and this was, say 1970-whatever, and it had a pool table on the top floor in a very traditional kind of divorced-dad apartment building,” said Mr. Eigeman, who grew up in Denver, Colorado, attending the Putney boarding school in Vermont. “It was just the sort of thing where we could play pool together and we could talk about the Broncos. And that was pretty much it.”

Later on, he found a worthy competitor in his now-wife, Linda, 42, against whom he’s been shooting pool since they met at Kenyon College. (Yes, except for a brief breakup followed by “a very long letter-writing campaign on both of our parts that I don’t think could happen today in the land of e-mail” they have been together that long. And to think, most of his characters could barely even date!) The two would play eight ball in halls near Gambier, Ohio, and later, once they moved to New York in the late 1980’s, at Julian’s, on 14th street, and Chelsea Billiards. The Eigemans have a pool table now in their upstate farmhouse, near Hudson. (It wouldn’t fit in their parlor floor brownstone apartment.)

“We’d play these first-to-200-wins—whoever wins 200 games could ask for whatever they wanted,” Mr. Eigeman said. “And she won the first one and I won the second and asked for a night at the Algonquin, and that’s where I asked her to marry me.” (Heart palpitations!) The actor-director has his wedding anniversary inscribed on the inside of his wedding band. “I was told to do this—it’s a very good idea,” he said sagely. Their 14th anniversary was earlier this month.

Before New York, the Eigemans did a brief stint in England. “I was going to be in an acting school in London and then I promptly got thrown out of an acting school in London,” he said. “Well, it wasn’t that I got thrown out as much as I was not invited back, which is the same thing, just more polite.”

Back on this side of the pond, Linda interned at CNN (she still works there, as a senior producer) while Mr. Eigeman parked cars at the River Cafe. (They’ve been in Brooklyn pretty much ever since; his neighbors include actor Gabriel Byrne and the novelist Arthur Phillips, with whom he frequently lunches.) Back then, he’d occasionally gamble away his night’s earnings—“I could lose a couple hundred dollars a night, and that was all I made the night before,” he said. “So it was like a zero-sum game. I lost everything.” Needless to say, Mr. Eigeman doesn’t gamble any more.

He is most frequently recognized for having played Max in Kicking and Screaming. His favorite “fan” story involves a fellow restaurant patron visiting his table and putting down a scrap of paper that read “Broken Glass,” an homage to a scene in Mr. Baumbach’s film when Max sees a pile of broken glass on the floor and puts a piece of paper over it saying “Broken Glass” instead of cleaning it up. “I was like, ‘That’s fantastic.’ It’s a huge compliment, it’s also very clever, it’s everything you want,” he said.

But nearly every role Mr. Eigeman has played has echoed his very first as Nick Smith in Metropolitan, which went on to earn an Oscar nomination for Mr. Stillman for best original screenplay.

“EVERYBODY SHOULD BE SO LUCKY that that would be their first film,” said Mr. Eigeman, who got the part after answering an ad in Backstage magazine. “Because it in a way was so extreme, it was really like acting, you were really swinging for the fences all the time. I’m not sure if I would have the balls to do that now. The bravery of ignorance is spectacular. But also you had to think like, this was 1990-whatever, one or two or something. Film was really happily sexual, dark. Sex, Lies and Videotape. Even Eating Raoul. … I was like, C’mon, this [Metropolitan] is crazy! And you know, it gives you brain freeze because you’re like, ‘I am going to do a 14-page monologue about collars and cummerbunds.’”

Speaking by phone from his home in Paris, Mr. Stillman said that Mr. Eigeman was “impressive right from the start.” He cast him as the lead in his next two films, despite the fact that by the time they made The Last Days of Disco in 1998, they were “under a lot of pressure not to work together again. People were worried about typecasting, and that he would be too associated with my films.” Disco’s producers wanted a star in the role of Des, the sleazy nightclub manager who breaks up with girls by telling them he might be gay. Mr. Stillman insisted, however, on Mr. Eigeman. “Chris was just so much better than anyone else,” he said.

Mr. Stillman suggested that possibly “the roles he’s played in my films do him a disservice, a bit.” But Mr. Eigeman begged to differ. In fact, he seemed downright content with his whole freaking life. “I’ve been really, really, really lucky because I’ve worked with some incredible directors and I did some films that people can look back on and think, ‘Oh that was a good film and that was of the time,’” he said.

And unlike his characters, he’s not afraid to grow up. Well, maybe.

“Even though I am in my mid-40’s I live like I am in my mid-20’s,” Mr. Eigeman said. “Like, if you turn the sound off, I don’t think there would be any real difference from my mid-20’s to my mid-40’s, and that’s all about to change.”