Hudson also co-founded Fabletics, a fitness brand and membership program operated by JustFab.
Hudson was born in Los Angeles, California, the daughter of Academy Award-winning actress Goldie Hawn and Bill Hudson, an actor, comedian, and musician. Her parents divorced when she was 18 months old and she and her older brother, actor Oliver Hudson, were raised in Snowmass, Colorado, and Pacific Palisades, California, by her mother and her mother's longtime boyfriend, actor Kurt Russell.
Hudson has stated that her biological father "doesn't know me from a hole in the wall", and that she considers Russell her father. Her biological father indicated that though he had made several efforts to connect with Kate and Oliver, neither of them reciprocated. Hudson has described her mother as "the woman that I've learned the most from, and who I look up to, who has conducted her life in a way that I can look up to". She has four half-siblings: Emily and Zachary Hudson, from her biological father's later marriage to actress Cindy Williams; Lalania Hudson, from his relationship with another woman; and Wyatt Russell, from her mother's relationship with Kurt Russell.
Hudson's ancestry is Italian (from her paternal grandmother), Hungarian Jewish (from her maternal grandmother), and the remainder a mix of English and some German. She was raised Jewish. Like her mother, Hudson practices Buddhism.
In 1997, she graduated from Crossroads, a college preparatory school in Santa Monica. She was accepted to New York University, but chose to pursue an acting career instead of an undergraduate degree.
Hudson's first film roles came in 1998 with two films: the comedy-drama Desert Blue and Ricochet River. She subsequently appeared in the 1999 New Year's Eve-set comedy ensemble comedy film 200 Cigarettes and the 2000 teenage drama Gossip. Regarding her early career and success, Hudson has noted that she is a "hard worker" and did not want to be associated with her well-known parents, wishing to avoid the perception that she "rode on somebody's coattails".
Hudson's breakthrough role was as Penny Lane in Cameron Crowe's Almost Famous (2000), for which she won the Golden Globe Award for Best Supporting Actress and was nominated for an Academy Award for Best Supporting Actress.
In 2002, Hudson starred in the remake of the historical romance The Four Feathers, which was panned by critics and audiences. Her next film, the romantic comedy How to Lose a Guy in 10 Days, was a box office success, grossing over $100 million after its February 2003 release. Hudson subsequently appeared in several romantic comedies, including Alex and Emma and Raising Helen; the films met with varying degrees of success. Hudson later headlined the 2005 thriller The Skeleton Key. The film, which had a production budget of $43 million, grossed over $91.9 million worldwide ($47.9 million in North America). Her next film, a comedy titled You, Me and Dupree and co-starring Owen Wilson and Matt Dillon, grossed $21.5 million on its opening weekend of July 14, 2006.
In 2007, Hudson directed the short film Cutlass, one of Glamour magazine's "Reel Moments" based on readers' personal essays. Cutlass co-stars Kurt Russell, Dakota Fanning, Virginia Madsen, Chevy Chase and Kristen Stewart. The following year, she appeared in the romantic comedy Fool's Gold, her second film co-starring with Matthew McConaughey; she was certified in scuba diving in the Great Barrier Reef for the movie's underwater scenes. She also appeared in My Best Friend's Girl, another romantic comedy, in 2008. Hudson next appeared in the musical film Nine, alongside Daniel Day-Lewis, Marion Cotillard, Penélope Cruz, Nicole Kidman, and Judi Dench. The film, directed by Rob Marshall, was released in December 2009. Hudson was critically acclaimed for her dancing skills, showcased in a 1960s-inspired original piece called "Cinema Italiano", which was written specifically for her character. She later starred in the film adaptation of Jim Thompson's The Killer Inside Me, which premiered at the 2010 Sundance Film Festival. In 2011, she starred in another romantic comedy, Something Borrowed, based on Emily Giffin's novel of the same name.
In 2012, Hudson was cast in the recurring role on Fox teen comedy series, Glee as Cassandra July, Rachel Berry's dance teacher at the fictitious New York Academy of the Dramatic Arts (NYADA). Hudson later went on to play supporting roles in smaller films, including Wish I Was Here and Good People. In 2016, she starred in the romantic comedy Mother's Day, opposite Jennifer Aniston and Julia Roberts, and played Mark Wahlberg's character's wife in the drama Deepwater Horizon, based on the Deepwater Horizon explosion.
In 2013, Hudson began a partnership with online fashion retailer JustFab to launch her own line of workout clothes and active wear called Fabletics.
In 2016, Hudson released her book, Pretty Happy: Healthy Ways to Love Your Body.
Hudson married Chris Robinson, the frontman for The Black Crowes, on December 31, 2000, in Aspen, Colorado. The couple's son, Ryder Russell Robinson, was born on January 7, 2004. They lived in a house that was once owned by director James Whale and traveled together during Hudson's film shoots or Robinson's music tours. On August 14, 2006, Hudson's publicist announced that Hudson and Robinson had separated. On November 18, 2006, Robinson filed divorce papers, citing "irreconcilable differences". The divorce was finalized on October 22, 2007, with Hudson being granted joint custody of Ryder.
In early 2006, Hudson sued the English version of the National Enquirer after it reported she had an eating disorder, describing her as "painfully thin". Hudson said the tabloid's statements were "a blatant lie" and she was concerned about the impact the false report could have on impressionable young women. The newspaper apologized and compensated her.
In early 2010, Hudson began dating Muse frontman Matt Bellamy. Hudson and Bellamy became engaged in April 2011 and their son, Bingham Hawn Bellamy, was born on July 9, 2011. On December 9, 2014, the couple announced that they had ended their engagement. However, Hudson and Bellamy are on good terms with one another, successfully co-parenting their son.
Hudson says that she does not enjoy seeing herself on screen, saying, "I get cold and I shake and I sweat" when watching her performances for the first time.
In 2016, Hudson said: "Meditation has been the most helpful and life-changing thing for me. You can feel the difference when you meditate on a regular basis. At least I can.... I started practicing transcendental meditation a year and a half ago so I meditate 20 minutes in the morning and I try to do another 20 minutes in the afternoon."Hudson, Kate (2016). Pretty Happy: Healthy Ways to Love Your Body. Farrar, Straus and Giroux. ISBN 978-0-06-243424-1.