Kondo has written four books on organizing, which have collectively sold millions of copies around the world. Her books have been translated from Japanese into several languages including Korean, Chinese, Spanish, Indonesian, Italian, French, German, Swedish, Portuguese, Catalan, and English. In particular, her book The Life-Changing Magic of Tidying Up (2011) has been published in more than 30 countries. It was a best-seller in Japan and in Europe, and was published in the United States in 2014.
In the United States and the United Kingdom, the profile of Kondo and her methods were greatly promoted by the success of the Netflix series Tidying Up with Marie Kondo, released in 2019, which gained Kondo a nomination for the Primetime Emmy Award for Outstanding Host for a Reality or Competition Program.
Kondo opened an online store called KonMari on 18 November 2019.
Kondo says that she has been interested in organizing since childhood. In junior school, Kondo ran into the classroom to tidy up bookshelves while her classmates were playing in physical education class. Whenever there were nominations for class roles, she did not seek to be the class representative or the pet feeder. Instead, she yearned to be the bookshelf manager to continue to tidy up books. She said she experienced a breakthrough in organizing one day, "I was obsessed with what I could throw away. One day, I had a kind of nervous breakdown and fainted. I was unconscious for two hours. When I came to, I heard a mysterious voice, like some god of tidying telling me to look at my things more closely. And I realized my mistake: I was only looking for things to throw out. What I should be doing is finding the things I want to keep. Identifying the things that make you happy: that is the work of tidying."
She spent five years as an attendant maiden at a Shinto shrine. She founded her organising consulting business when she was 19 and a sociology student at Tokyo Woman's Christian University. In her senior year, she wrote her capstone thesis, titled "Tidying up as seen from the perspective of gender".
Kondo's method of organising is known as the KonMari method, and consists of gathering together all of one's belongings, one category at a time, and then keeping only those things that "spark joy" (Japanese language ときめく tokimeku, translated as equivalent to English "flutter, throb, palpitate"), and choosing a place for everything from then on. Kondo advises to start the process of tidying up by "quickly and completely" discarding whatever it is in the house that doesn't spark joy. She advises to do this by category of items and not their location in the house. For example, all the clothes in the house should be piled up first, assessed for tokimeku, and discarded if not needed, followed by other categories such as books, papers, miscellany, and mementos. Another crucial aspect of the KonMari method is to find a designated place for each item in the house and making sure it stays there.
Kondo says that her method is partly inspired by the Shinto religion. Cleaning and organising things properly can be a spiritual practice in Shintoism, which is concerned with the energy or divine spirit of things (kami) and the right way to live (kannagara):
"Treasuring what you have; treating the objects you own as not disposable, but valuable, no matter their actual monetary worth; and creating displays so you can value each individual object are all essentially Shinto ways of living."
A two-part TV dramatisation was filmed in 2013 based on Kondo and her work, titled 人生がときめく片づけの魔法 (Jinsei ga Tokimeku Katazuke no Mahō). She has lectured and made television appearances. She released a series of videos teaching "the best way to fold for perfect appearance".
On 1 January 2019, Netflix released a series called Tidying Up with Marie Kondo. In the series, Kondo visits various American family homes full of clutter and guides the families in tidying up their houses through her KonMari method. Following the release of her Netflix series, Kondo was the subject of various Internet memes. A clip of her saying "I love mess" included on Time's list of the ten best memes of 2019.
Kondo married Takumi Kawahara in 2012. At the time they met, Kawahara was working in sales support and marketing at a corporation in Osaka. Once Kondo's career took off, he left his job to become her manager and, eventually, CEO of Konmari Media, LLC. The couple have two daughters, Satsuki and Miko. Kondo announced on January 27, 2021 that she is expecting a third child. She gave birth to a baby boy on April 22, 2021.