In a couple of scenes in Noam Murro’s Smart People, Dennis Quaid’s face becomes a malleable mask of sickly, embarrassed insincerity and passive-resistant condescension. It’s a lot to convey in one brief take, but Quaid manages it.

Quaid is portraying Lawrence Wetherhold, a neurasthenically self-absorbed English professor at Carnegie Mellon. In one of those two scenes, Wetherhold is responding to a challenge from a student who accuses the prof of not remembering him despite having had him in another class. Wetherhold’s denial is less than convincing, since he’s trying to cop a glance at the seating chart as he demurs.

In this and a number of other scenes, Quaid is consistently amusing, and occasionally affecting, in his portrait of a cynically disaffected and depressed academic, widowed parent, and, eventually, lover. He’s also more amusing and affecting than most of the movie he’s in.

Smart People is a domestic and romantic comedy that aims for those qualities, and it has its moments of wryness and gentle, sympathetic humor. But it’s not up to the level of its star.

He’s been here before. His embattled corporate executive was about the only interesting element of 2004’s otherwise forgettable In Good Company. Fourteen years back, in Lawrence Kasdan’s long, sometimes logy Wyatt Earp, Quaid’s elegantly dissipated Doc Holliday was a welcome diversion (and better than Val Kilmer’s more remarked-on baroque Holliday in Tombstone the year before).

Ellen Page and Dennis Quaid in Smart People

Quaid’s almost simultaneously defensive and patronizing professor in Smart People is a good distance from the self-confident characters he played in his younger years, like the heroic astronaut in The Right Stuff and the cocksure cop of pliable virtue in The Big Easy. That’s a measure of his reliable, admirably plastic skills. His Wetherhold veers toward crude caricature sometimes, but Quaid avoids the detour.

But he and the rest of the movie’s accomplished cast aren’t always given enough to work with. Debuting screenwriter and novelist Mark Jude Poirier has said his screenplay began as an idea for a novel, and it sometimes seems to be stuck around that point. The movie is a curious exception to common film-world practice: stripping off superficial narrative components from a novel and amalgamating them into a movie’s story line. This time, the movie seems too loose and underwritten, as if the ideas hadn’t been worked out in the first place.

Smart People primarily tracks Wetherhold’s slow, balky, and incomplete transition from self-regarding, withholding jerk to an internship in mensch-making and responsibility-taking parenthood. He undertakes his moral journey chiefly via a romance with a doctor (Sarah Jessica Parker) who was once his student. (He gave her term paper on Middlemarch a C.)

Along the way, he rather belatedly tries to engage with his virtually adult offspring, especially his acerbically mouthy but repressed 17-year-old daughter (Ellen Page of Juno fame), a girl with decided Oedipal and reaction formation issues. And he’s assisted in his cautious reopening to the world by the unlikely reforming influence of his amiably aimless stoner of an adoptive brother (Thomas Haden Church, coming off as a smarter, educated version of the title character of TV’s My Name Is Earl).

Smart People is certainly pleasant, and on occasion even sharply droll. But it never really achieves much momentum, and things seem to trail off at the end in a convenient wrap-up. First-time feature director Murro has an appropriately light touch, but his movie lacks some comic verve. A crucial piece of business near the end involving an ancient student evaluation of Wetherhold is muddled.

Unlike another, better literary-academic comedy, Curtis Hanson’s 2001 Wonder Boys, Smart People’s comic and romantic problems aren’t so much worked out and elaborated as they are carried along and then disposed of. (From the look of things, it was partly filmed in the same Pittsburgh neighborhood as the earlier movie.)

On the other hand, Smart People has a relaxed, congenial tone and, please trust me, there are a lot of purported romantic comedies out there of which this cannot be said. And they don’t have Dennis Quaid.