The film opens in the late 1980s with Joy living with her two young children, ex-husband Tony (Édgar Ramírez), mother (Virginia Madsen) and beloved grandmother Mimi (Diane Ladd) working a job she hates. Grandma Mimi's voiceover tells us of how creative and inventive Joy was as a child, but that she had to put aside her dreams to help her parents through their divorce and support her family. Indeed: she is the one they all rely on for help, whether it's her useless mother Terry, who spends all day in bed watching soap operas, the characters of which she cares about more than her real family, or her father Rudy (Robert De Niro), who needs a place to stay after splitting up with his latest woman.
While the family is taking a boat trip with Rudy's wealthy new love interest Trudy (Isabella Rossellini), Joy cuts her hand while cleaning glass from a mop and within hours, she has come up with a design for a self-wringing mop. She persuades her father and a grudging Trudy to provide some financial assistance to help her turn her Miracle Mop dream into a reality and then sets about making it happen, helped along the way by Tony ("they were the best divorced couple in America"), her best friend Jackie (Dascha Polanco) and a QVC executive (Bradley Cooper). The rest of her family — particularly her jealous half-sister Peggy (Elisabeth Röhm) — remain skeptical in Joy's abilities and business acumen as she faces setback after setback. They tell her that she dreamed too big and urge her to scale back her expectations.
But Joy will do no such thing. In anyone else's hands, Joy would probably come across as naive, foolhardy and almost parodically earnest and determined. With Lawrence's subtle and masterful performance, however, Joy is extremely likeable and passionate. We root for her throughout and want her to prove her family wrong. The film doesn't take itself too seriously either: Grandma Mimi's tongue is firmly in her cheek as she delivers her voiceovers, and the frequent dives into Terry's soap operas keep it from becoming too worthy or guileless. Beyond our eponymous heroine, though, the characters are somewhat two-dimensional and the dialogue doesn't sparkle as much as it could.