Plot[edit]

In 1990, Joy Mangano is a divorced mother of two, working as a booking clerk for Eastern Airlines. She lives with her two young children, her mother Terri, her grandmother Mimi, and her ex-husband Tony in working-class Peconic, New York. Her parents are divorced, and her mother and father fight whenever her father shows up at her home. Joy's older half-sister, Peggy, is an overachiever who constantly humiliates Joy in front of her children for her failed marriage. Peggy and Joy's father Rudy are very close. Terri spends all day lying in bed watching soap operas as a means of escape from her life, leaving Joy to run the household. Only Joy's grandmother and her best friend Jackie encourage her to pursue her inventing ambitions and become a strong successful woman.

After divorcing his third wife, Joy's father starts dating Trudy, a wealthy Italian widow with some business experience. While on Trudy's boat, Joy and her family drop their glasses of red wine, and she attempts to mop up the mess. While doing so, Joy cuts her hands on the broken glass while wringing the mop. Joy returns home and creates blueprints for a self-wringing mop. She builds a prototype with help from the employees at her father's shop. She then convinces Trudy to invest in the product. They make a deal with a company in California, owned by a man in Dallas, to manufacture the mop's parts at a low price. In order to avoid a potential lawsuit, Joy also pays $50,000 in royalties to a man in Hong Kong who supposedly has created a similar product. When the company repeatedly bills Joy for faulty parts they create, Joy refuses to pay the fees and tells her father, Trudy, and Peggy not to pay them.

Joy needs a quick, easy way to advertise her product, and is able to meet with QVC executive Neil Walker, with the help of Tony, who despite being divorced from Joy, remains close with her. Neil is impressed and shows Joy his infomercials, where celebrities sell entrepreneurs' products through a telethon system. Neil tells Joy to manufacture 50,000 mops. Joy is advised by Rudy and Trudy to take out a second mortgage on her home, in order to pay her costs. The first infomercial fails, due to the celebrity Neil chose to advertise the product having no clue how the mop works properly, but the next day she goes straight to QVC and convinces Neil to let her do the infomercial. Once the second infomercial is done, Joy and her product become an overnight success. Things look up for the family, with the mop earning thousands of dollars on QVC, and Terri falls for Toussaint, a Haitianplumber Joy hired to fix a leak in Terri's bedroom, something Terri has not done since her divorce with Rudy and other than watching her soap operas.

Joy's grandmother dies suddenly, after the running success. Rudy and Trudy send Peggy to California to conduct Joy's company business. Afterwards Peggy tells Joy that she paid the excessively raised production fees, despite Joy telling them not to pay them. She now claims to Joy that she and Rudy have a product of their own to send to QVC which they believe will be better than Joy's. Joy is angry and travels to California to meet with the manufacturer, who refuses to pay her back. Joy discovers that the manufacturer is about to fraudulently patent her design and claim that they were the ones who originally created the mop. Trudy's lawyer reveals that there is nothing they can do to prevent this, since Peggy paid the excessive fees and Joy is forced to file for bankruptcy. Joy discovers that the manufacturers have been defrauding her the entire time she has dealt with them. Upon learning this, she travels to Dallas to confront the owner, Derek Markham. She reveals to Markham that she made a call to the man she supposedly paid the royalties to in Hong Kong, to explain about the product, but that he told Joy that he had no knowledge of the mop being made or of any royalties being paid, proving that Markham and the manufacturing company are committing fraud and embezzlement, which forces Markham to pay Joy back. In the following scene, Joy is seen standing underneath a Snowmaker in Dallas, looking confident. She smiles, and slowly walks away, as Cream's "I Feel Free" plays in the background.

Several years later, Joy is a wealthy, successful businessperson who helps other young inventors develop their ideas. Jackie and Tony remain her most valued advisors. Joy continues to take care of her father, despite him and Peggy having unsuccessfully and wrongly tried to sue her for ownership of her company. Terri is the only family member who does not live off Joy, finally finding stability through her relationship with Toussaint.