Parker Posey emerged from her downtown Manhattan lobby in a zip-up black jumpsuit streaked with white, her newly blond hair in a cotton candy nimbus. She could have passed for Daryl Hannah in “Blade Runner” were it not for the fluffy white Bichon-Maltese poodle at her feet.

“When it gets to be summer, she knows it’s ice cream time,” Ms. Posey said of her beloved dog, Gracie, who is nearly as recognizable (and unpredictable) a downtown celebrity as she is. (As a Gawker headline once put it, “Parker Posey’s Dog Is the Devil.”)

With the leash looped around her waist like a belt, Ms. Posey led Gracie east to an ice cream parlor, where she ordered two peppermint scoops with an extra cup, then took over a townhouse stoop across the street and fed Gracie her portion.

“I’ve had her for 11 years,” she said. “She’s into her old-lady stage, just like her mommy.”

Of course, 46 is old only in Hollywood years. But it does point to a dilemma that is perhaps distinct to Ms. Posey: How does an actress who follows her own weird wavelength navigate an industry that tends to ignore women over 40 while staying true to what made her an unorthodox star in the first place?