Star performances propel the made-in-New Orleans “Black or White.” A script that has an identity crisis, however, weighs the movie down, pulling it into messy dramedy.

Kevin Costner stars as the well-meaning, well-to-do guardian of his biracial granddaughter, Eloise. Costner’s daughter, the girl’s teen mother, died in childbirth. Eloise’s absent father has been in and out of prison.

Eloise’s white grandparents have raised her as their own. She calls Costner’s character, Elliott Anderson, papa. As best as moviegoers call tell at the dramatic point during which they are dropped into “Black or White,” the grandparents and their grandchild have been living a happy, loving life together.

“Black or White” begins with a new tragedy for the Anderson family. The shattered Elliott sits in a hospital hallway. His wife, Eloise’s grandmother, has been killed in an auto accident.

Next morning, Eloise, played by 7-year-old actress Jillian Estell in her feature film debut, asks her grandmother, “Where’s grandma?” Is grandma gonna take me to school?”

Elliott stalls as he struggles to comb the girl’s mass of corkscrew curls. After school, during one of the film’s intimate and genuinely affecting scenes, Elliott tells Eloise the awful news.

Written and directed by Mike Binder, who previously directed Costner in the better focused “The Upside of Anger,” “Black or White” wanders from gentle comedy to good drama to mannered melodrama.

The movie tiptoes around race. In an era when racial divisions have flared into real-life national drama, “Black or White” doesn’t make great impact.

As the grieving Elliott struggles, self-medicating himself with drink, Costner works through an admirably sincere portrayal of this man in crisis. The actor may never have looked so lost on screen.

Oscar winners Costner and, playing Eloise’s paternal grandmother, Octavia Spencer, share many scenes together.

Spencer’s irrepressible Rowena Jeffers rules a sprawling, extended family and operates six successful businesses in South Central Los Angeles. On paper, Rowena looks like a superwoman, but Spencer eases into the role with down-to-earth authenticity.

No-nonsense Rowena knows what she thinks is right for Eloise. She wastes no time letting Elliott know her position.

“She’s got a whole lot of family with us,” Rowena tells Elliott after his wife’s funeral. “I’m this girl’s grandmother, whether you like it or not.”

The thorny conversations about where Eloise will go continue all the way to the courtroom. On the way, the child’s father, Reggie (André Holland) surfaces for increasingly disturbing appearances.

The movie’s false notes include Rowena’s belief in her troubled son, a man who’s obviously not responsible enough to raise a child. Reggie’s behavior pushes the film into the sabotaging melodrama.

New Orleans native Anthony Mackie co-stars as Rowena’s attorney brother, Jeremiah. It’s a feisty performance packed with certainty. Jeremiah wants to make the custody case between Rowena and Elliott a matter of black and white. The race card he plays hinders the story with heavy-handed machinations.

Inevitably, there’s a big courtroom scene, which Costner makes the most out of it. His performance, in and out of court, and the dueling scenes he and Spencer engage in are “Black or White’s” strong suits.