Director David O. Russell explores the nooks and crannies in the life and work of Joy Mangaro (Jennifer Lawrence), an inventor and entrepreneur who proves her mettle and perseverance in the creation of new kind of mop. After cutting her hand wringing out a regular mop, she comes up with an idea for a mop with a plastic tube to do the wringing and a mop head that is not only absorbent but can be detached and tossed in the washing machine. Her story of success is narrated by Joy's beloved grandmother (Diane Ladd) who provides the encouragement, love, and appreciation Joy needs to arrange financing, manufacturing, and marketing for the mop.
When we first meet her, Joy is raising her two young children in a household consisting of her shut-in mother Terry (Virginia Madsen), who does nothing but watch TV soap operas and criticize her daughter, and her ex-husband Tony (Edgar Ramirez), an aspiring club singer who lives in the basement. Then her father Rudy (Robert De Niro) also moves into the basement. He's a cranky and opinionated man who runs an auto shop with Joy's half-sister Peggy (Elizabeth Rohm), a woman who is intensely jealous of her.
Joy creates a prototype of her new mop and manages to get her father's new girlfriend Trudi (Isabella Rossellini) to invest in the product. Knowing that promotion is the key to success, Joy luckily hooks up with QVC executive Neil Walker (Bradley Cooper), who senses that this talented and honest woman can make it big if handled right. After one of the top salesmen on the network bungles the introduction of the mop on TV, Joy goes on TV herself to demonstrate her invention and sales go through the roof. But there are many other setbacks and shocks along the way to success.
Joy is propelled by the energetic full-throttle power of Jennifer Lawrence's performance and the clever comic sequences orchestrated by director David O. Russell. He's already shown us (I Heart Huckabees, Silver Linings Playbook) his knack for presenting the family circle as a training ground for making it or failing in the public realm where dreams are tested. Here, it is the unconditional love of her grandmother that carries Joy through a series of depleting crash-and-burn trials and tribulations.
One of the many messages in this dramedy is that money and family solidarity usually do not mix. Keep them separate, and you might just be fortunate enough to have every little thing turn out alright.