When I was going through another miserable day of my graduate course during the early 2010s, it happened to be my turn to clean the floor of my laboratory, and I used a newly bought mop for the first time. While equipped with a bucket for washing water, the mop was capable of self-wringing through its clever handle design and a spinning basket in the bucket, and it was one of a few commercial cleaning tools which really impressed me for inventiveness and convenience. I did not have to wet my hands or bend my back for washing the mop, and, of course, I got extra time for my procrastination through this convenient mop.

While the Miracle Mop invented by Joy Mangano in 1990 looks different from the one I used, I instantly recognized the same mechanism of self-wringing when her mop was shown in “Joy”, which is loosely based on Mangano’s real-life story. Although it is not perfect at all in its uneven tone and incoherent narrative, everything in the film is somehow held together to some degrees thanks to its exceptional actress’s star presence, and I even came to be a bit easy on its last-minute contrivance which could have annoyed me a lot.

After the offbeat prologue which briefly depicts her childhood years along with her grandmother’s sweet narration, we meet Joy Mangano (Jennifer Lawrence), a struggling divorced mother of two children who has been stuck in a drab life of constant problems to be taken care of by her. When she was young, she was a bright kid full of hope and aspiration, but her dream of inventing useful things seems to be out of her reach at present as she is busy with supporting not only her two children but also the other members of her dysfunctional family. While her two kids are taken care of well by her grandmother Mimi (Diane Ladd), Joy’s mother Terri (Virginia Madsen) spends most of her days with her favorite TV soap drama, and her ex-husband Tony (Édgar Ramírez, who is far from his gritty turns in “Carlos” (2010) and “Zero Dark Thirty” (2012)) is still living in the basement although they got a divorce two years ago.

And there is her father Rudy (Robert De Niro), who left his family a long time ago but has been around the family while running his local garage which happens to have a shooting range right next to it. She lets her father in the family house after his third marriage failed, and Tony is not so pleased to share his place with his ex-father-in-law who does not think highly of him. She also takes care of her father’s messy accounting matters, but she is not appreciated much by him or her petty half-sister Peggy (Elisabeth Röhm), who frequently disregards Joy whenever it suits her.

When she happens to lose her recent job, Joy becomes more desperate, but then she gets one good idea of invention, and, fortunately, she comes across an opportunity to commercialize her idea. She manages to convince Rudy’s rich girlfriend Trudy (Isabella Rossellini) to invest a considerable amount of money to her idea, and, mainly thanks to Tony, she luckily meets Neil Walker (Bradley Cooper), an executive of an influential TV home shopping network company who sees the potential from her and her invention.

While this is a familiar rags to riches story, the screenplay by the director David O. Russell and his co-writer Annie Mumolo  is mostly engaging although not all of its attempts work. Some of the supporting characters in the film are too broad or underdeveloped, and the plot often goes astray as juggling its many elements. In case of a major conflict during its third act, it is resolved too quickly and artificially for the feel-good ending to be delivered, and the ending itself is overlong in its sentimental mood.

In spite of its glaring flaws, the movie has a number of things to entertain us even while it stumbles here and there. I was amused by how Russell uses Terri’s favorite soap TV drama during some of its comic moments (Russell actually hired real soap TV drama performers to play those soap TV drama characters in the film, by the way), and there is a breezy scene where Neil shows Joy how things work in his workplace. As Joy looks around the place along with Neil, his employees busily work for whatever to be advertised and sold to their many viewers around their local region, and it is hard to be cynical about the excitement in the air whenever a product gets thousands of calls from customers hooked by its infomercial.

Since her breakthrough turn in “Winter’s Bone” (2010), which is still her best moment to date, Jennifer Lawrence has been a force of nature in Hollywood along with her stellar performances including an Oscar-winning turn in “Silver Linings Playbook” (2012), and she radiates with her own star quality as usual here in this film. Thanks to her natural charm, we instantly like Joy and then come to root for her, and Russell surely knows how to use his star actress’s talent to full effect during several fine moments which led to her fourth Oscar nomination a few days ago. While prominent performers like Robert De Niro, Édgar Ramírez, Virginia Madsen, Isabella Rossellini, Diane Ladd, and Bradley Cooper come and go around her, Lawrence keeps commanding her scenes as the star of the film, and that takes me back to how she diligently supported the Hunger Games series even when it began to lose its steam during its two-part final chapter.

As he did in his previous films including “Silver Linings Playbook”, and “American Hustle” (2013), Russell assembles a group of his usual performers and tries to roll them together for another fun to have, but the result is less satisfying in comparison while being a bit more focused than “The Fighter” (2010) thanks to Lawrence’s plucky central performance. She is only 25, but it seems nothing can possibly stop this smart talented actress’s ongoing advance, and she definitely proves it again here as swiftly mopping the floor for her imperfect film.