Robert De Niro has a juicy role in Paul Weitz’s film based on Nick Flynn’s memoir about his strained relationship with his father, and he seizes on it with an intensity that reeks of ham. The over-the-top quality of De Niro’s turn in “Being Flynn” is thrown into even sharper relief by the fact that he’s playing the boozy, volatile Jonathan Flynn against Paul Dano, whose performance as his son is so low-key and mannered that it seems to inhabit an entirely different thespian universe. That doesn’t mean that the film is uninteresting. But it is oddly misshapen and uneven.

Weitz constructs “Flynn” as a sort of joint biography with the two men alternately narrating, though of course Jonathan’s voice is actually reflected through Nick’s authorial imagination. As the film begins, Nick is a rootless, jobless young man grieving—as we will learn—the suicide of Jody (Julianne Moore), the hardworking, loving mother who raised him alone after they’d been abandoned by Jonathan nearly two decades earlier. He wants to write, but is much less sure of his talent than his father, a racist, viciously homophobic alcoholic who introduces himself as one of America’s three great writers (the others being Twain and Salinger) and is constantly proclaiming publishers’ interest in his magnum opus, still in progress, while keeping himself afloat by driving a cab.

Nick’s search for a place to stay takes him to an abandoned club whose residents—a gay white man and a black drug dealer (Chris Chalk and Thomas Middleditch)—accept him as a roommate. It’s there that he meets Denise (Olivia Thirlby), a grounded, sophisticated girl who convinces him to take a job at the homeless shelter where she works. Meanwhile Nick’s been abruptly contacted by his long-absent father, who asks for help moving his stuff into storage, since he’s been evicted from his apartment after a violent altercation with his neighbors. Their initial meeting is no lovefest, and Nick assumes it’s a one-off; but Jonathan soon loses his job as a cabbie and eventually winds up as a guest at the shelter where Nick now works.

Having to deal with his unruly, psychologically tortured parent has a damaging effect on Nick, and despite the support of Denise and other co-workers he falls into addiction himself, worried that the blight that’s consumed his father might also be his fate. The fact that the film is based on his memoir, of course, forecasts that he’ll eventually come out of his funk, but Jonathan’s end is far less certain.

The title that Weitz has chosen for his film is a somewhat ambiguous one—does it refer to Jonathan or Nick or both? Both men receive approximately equal screen time, but of necessity the emphasis, in terms of content, is on the younger man. We learn much more about the events that have shaped his psyche via some affecting flashbacks (in many of which he’s played by young Liam Broggy)—including one bit of narrative shorthand, a cleverly choreographed non-stop sequence in which he’s shown playing catch with a variety of his mother’s boyfriends. By contrast Jonathan is presented fully-formed and, to be honest, pretty one-dimensional.

Yet in the playing, De Niro’s ferocity is so extreme that it throws Dano’s more subtle work into the shade. Jonathan takes center stage as a result, which undermines the story’s balance. Even in the final scene, when Nick has overcome his demons and established himself as a writer, De Niro seizes pride of place and has the last word, even though he claims to be giving it to his son.

Of course it’s fun to watch De Niro go for broke this way, and one can appreciate the nuances in the work of the tall, gangly Dano, one of the most interesting actors of his generation. Moore captures a range of emotion in her brief appearances, Thirlby cuts a stern, elegant figure, and a fine supporting cast—including Lili Taylor as a shelter staffer—add resonance to the portrait of the Boston underclass Weitz draws, assisted by Sarah Knowles’ production design, Ryan Heck’s art direction, Susan Perlman’s set decoration, Aude Bronson-Howard’s costumes, and Declan Quinn’s hyper-naturalistic cinematography.

But despite all the talent in front of the camera and behind it, “Being Flynn” ends up the sort of picture one can respect more easily than feel. In the end you find yourself appreciating the acting instead of being moved by the plight of the characters. The result is a near-miss that doesn’t quite work either intellectually or emotionally.