Born into a privileged background, she was the oldest child of Isoko Isuda, a member of one of Japan's wealthiest banking families, and Eisuke Ono, who sacrificed a career as a classically-trained pianist to work as a banker. She attended the exclusive Gakushuin academy in Tokyo from primary school to the college division. Ono has mentioned in interviews that her parents left the upbringing of her and her younger brother to nannies; her parents were often distant, emotionally and physically. During World War II, the Ono family survived the bombing of Tokyo in an underground shelter. Ono and her siblings fled to the countryside, and were forced to beg for food while pulling their belongings in a wheelbarrow. It was during this period in her life she developed what some would refer to as her "aggressive" attitude; local children taunted the once well-to-do Yoko and her brother, now reduced to poverty. Determined to protect herself and her brother, she learned to maintain a tough exterior to hide her fear. Her father remained in the city and, unbeknownst to them, was incarcerated in a prisoner of war camp in China. After the war, Ono's family moved to Scarsdale, New York. She soon enrolled in Sarah Lawrence College. While her parents approved her choice of college, they were dismayed at her lifestyle, and often chastised Ono for befriending people they considered to be "beneath" her. In spite of this, Ono loved meeting artists, poets, and people who represented the "bohemian" freedom she longed for herself. Visiting galleries and art "happenings" in the city whetted her desire to publicly display her own artistic endeavors. In 1956, she married composer Toshi Ichiyanagi. They divorced in 1962. On November 28 that same year, Ono married American Anthony Cox. Cox was a jazz musician, film producer, and art promoter. Their marriage was annulled on March 1, 1963; they re-married on June 6, and finally divorced on February 2, 1969. Their daughter, Kyoko Chan Cox, was born on August 8, 1963. After a bitter legal battle, Ono was awarded permanent custody of Kyoko. However in 1971, Cox, who had become a Christian fundamentalist after his divorce from Ono, abducted Kyoko and vanished. Ono and her daughter were finally reunited in 1998.

Ono performing "Cut Piece". Ono was an early member of Fluxus, a loose association of avant-garde artists that developed in the early 1960s. Ono was among the first artists to explore conceptual art and performance art. An example of her performance art is "Cut Piece", during which she sat on stage and invited the audience to use scissors to cut off her clothing until she was naked. An example of her conceptual art includes her book of instructions called Grapefruit. This book, first produced in 1964, includes surreal, Zen-like instructions that are to be completed in the mind of the reader, for example: "Hide and Go Seek Piece: Hide until everyone forgets about you. Hide until everyone dies." The book was published several times, most widely distributed by Simon and Schuster in 1971, and reprinted by them again in 2000. Ono was also an experimental filmmaker. She made sixteen films between 1964 and 1972, and gained particular renown for a 1966 film called simply No. 4, but often referred to as "Bottoms". The film consists of a series of close-ups of human buttocks as the subject walks on a treadmill. The screen is divided into four almost equal sections by the elements of the gluteal cleft and the horizontal gluteal crease. The soundtrack consists of interviews with those who are being filmed as well as those considering joining the project. In 1996, the watch manufacturing company Swatch produced a limited edition watch that commemorates this film. Ono's work may best be appreciated by an open mind. She has been described as "the world's most famous unknown artist: everybody knows her name, but nobody knows what she does." Ono has sometimes been maligned and vilified by critics who condemn her art. For example, Brian Sewell, art critic for the London Evening Standard and television personality, said: "She's shaped nothing, she's contributed nothing, she's simply been a reflection of the times...I think she's an amateur, a very rich woman who was married to someone who did have some talent and was the driving force behind the Beatles. If she had not been the widow of John Lennon, she would be totally forgotten by now...Yoko Ono was simply a hanger-on. Have you seen her sculpture or paintings? They're all awful." However, the more common critical opinion is that Ono's work has been misunderstood and that it deserves attention and respect. Many scholars, art critics and members of the media have begun to reassess her art and to examine it seriously. In the past few years, Ono's work has regularly received recognition and acclaim. For example, Matthew Teitelbaum, director of the Art Gallery of Ontario, believes that "Yoko Ono is one of the world's most original and inspirational visual artists." Michael Kimmelman, the chief Art critic of the New York Times, wrote: "Yoko Ono's art is a mirror—like her work 'a Box of Smile,' we see ourselves in our reaction to it—a tiny prod toward personal enlightenment, very Zen." In 2001, YES YOKO ONO, a forty-year retrospective of Ono's work received the prestigious International Association of Art Critics USA Award for Best Museum Show Originating in New York City. (This award is considered one of the highest accolades in the museum profession.) In 2002 Ono was awarded the Skowhegan Medal for work in assorted media. And in 2005 she received a lifetime achievement award from the Japan Society of New York. Ono received an honorary Doctorate of Laws from Liverpool University in 2001; in 2002 she was presented with the honorary degree of Doctor of Fine Arts from Bard College. Scott MacDonald, visiting professor of film at Bard, said: "She is to be congratulated for the body of work she has made, and celebrated for what she has come to represent, within media history and throughout the world: courage, resilience, persistence, independence, and, above all, imagination, and a belief that peace and love remain the way toward a brighter, ever-more-diverse human future."