Kevin Smith is the writer/director of some of the most cheerfully profane and wildly politically incorrect movies of all time, including Clerks, Dogma, and Chasing Amy. His characters — and his scripts — are often immature and outrageous. But Smith’s brilliantly original dialogue and essential sweetness transcend the vulgarity and give his movies heart and soul. I am always curious to see what he does next.

“Jersey Girl” is a transitional film for Smith, interesting for its sense of where he is going but not successful in its own terms. This least conventional of movie makers has taken on the most conventional of movie plots — a widower bonding with his child, finding a new love, and finding himself — something covered in dozens of Hallmark Hall of Fame Father’s Day specials. And he gives it to us straight, with very little to make it fresh or vivid.

Ollie (Ben Affleck) has it all — a successful career as a publicist for pop stars and a beautiful wife (Jennifer Lopez). When she dies in childbirth, he is shattered. He turns the baby over to his father (George Carlin) and throws himself into his work.

But we all know what happens next. Ollie falters at first but then discovers how much he loves that baby. He loses his big fancy job and ends up driving a street sweeper like his father so he can take care of her. Seven years later, she has grown up into an adorable movie tyke named Gertie (the very talented Raquel Castro), and he is just about ready to begin to notice the very pretty girl (Liv Tyler) at the video store. Then we’re ready for the big crisis — will Ollie go after that big fancy new job or will he be there for Gertie’s school talent show? See if you can guess!

Oh, Kevin, Kevin, Kevin. You once gave us dialogue that was sublime slacker poetry, with knowing riffs on everything from John Hughes movies to God’s sense of humor. The jokes in this movie are so flat, so easy, so boring. Can you really think it’s funny to have Ollie, circa 1997, try to persuade reporters that George Michael is “all about the ladies?” And a “meet cute” over bisexual porn in the video store? Having a young child sing Mrs. Lovett’s role in “Sweeney Todd” at a school production isn’t as charming as you think it is (though it is pretty funny that all of the other children perform numbers from “Cats”). The two barflies who act as Gertie’s “uncles” aren’t as cute as you think they are. Bart’s alcohol problem comes and goes for the convenience of the script; it’s there when Ollie needs to make a wisecrack but never creates a problem for him in taking care of Gertie or doing his job.

The “playing doctor” scene and subsequent twist feels like a “very special” episode of “Full House” to the tune of “The Cat’s in the Cradle.” The best Ollie can do in explaining what attracts him about going back to his old life in Manhattan is to say that he misses eating sushi and hailing cabs. Gertie talks like a movie kid, or worse, a sitcom kid. The movie’s climax features an intervention by a real-life movie star who explains what life is all about, followed by an artificial “will he make it in time even though the street is blocked” that has a complete absence of energy or suspense. Is it possible for a movie to jump the shark?

Affleck has some affecting moments and Tyler’s offbeat warmth makes their scenes together work better than they have a right to. Castro transcends her character’s faux adorability with some real star power. But the formulaic script and uneven tone make this film a real disappointment. This genre — and this message — is so new to Smith, he did not feel he had to make it new for those of us who have seen this kind of thing over and over again. But I still look forward to seeing what he does next.

Parents should know that this movie has very strong language and sexual references for a PG-13. Ollie and Maya talk about pornography and masturbation and she offers him a “pity jump.” Ollie walks in on Gertie and a friend playing doctor and Gertie walks in on Ollie and Maya in the shower (with clothes on). There is brief diaper humor. Characters drink and smoke (references to alcohol abuse) and there is a cocaine joke. A scene from a theatrical production of “Sweeny Todd” includes cutting a man’s throat. One strength of the movie (as in all Smith movies) is the very positive portrayal of inter-racial relationships, including a loving marriage.

Families who see this movie should talk about how they balance their family and work responsibilities. What are some of Ollie’s alternatives? Do you think Ollie is a good father? Do you think Bart is a good father? Sometimes families are made up of people who are related to each other, and sometimes they are made up of people who just care about each other.

Families who enjoy this movie should check out Kevin Smith’s very entertaining and interactive website. They might also like to see some other movies with similar themes, like The Courtship of Eddie’s Father, Baby Boom, Kramer vs. Kramer and About a Boy.