She was a daughter of Viktor and Traute Gessner and born in Troppau, Silesia, Austria-Hungary (now Opava, Czech Republic), the second of three girls. Her parents divorced when she was 10 and she was sent to live with her grandmother. In her autobiography The Searching Spirit she wrote about her beloved grandmother Oma: "It is to her I owe anything that may be good in me."[citation needed] As a young adult, she considered the careers of concert pianist and medicine before adventure took her away from Europe. As an adult, she was distant from most of her family. After her first love affair left her heartbroken, she married three times in the span of ten years. Her first marriage was to a Jewish-Austrian, Viktor von Klarwill (Ziebel) who during World War II sent her to Africa to find a safe place for the two of them to live out. There she met and married the botanist Peter Bally, who gave her the nickname "Joy." She met her third husband, game warden George Adamson, while on safari in the early 1940s. They made their together home in Kenya.

Adamson appeared in "The Bargain" and "Death Walks by Night," two second-season episodes of the British television crime drama The Vise, which were broadcast in 1955.

Joy Adamson is best known for her conservation efforts associated with Elsa the Lioness. In 1956,her husband George Adamson, in the course of his job as game warden of the Northern Frontier District in Kenya, shot and killed a lioness as she charged him and another man. Adamson realized that the lioness was protecting her cubs which were later found nearby, Taking them home, he and Joy Adamson would raise the cubs. Early on, George Adamson attended to their physical needs while Joy Adamson and her pet Pati-Pati, a rock hyrax, raised them. Joy was completely devoted to the cubs from the beginning and named them "Big One", "Lustica" and "Elsa". After six months, it became apparent that three growing cubs were too much for the Adamsons and their staff. The two larger cubs, Lustica and the Big One, were sent to a zoo in Rotterdam, but they held back the third, Elsa. Deciding to set Elsa free rather than send her to a zoo, they spent many months training her to hunt and survive on her own. They were successful in the end: Elsa became the first lioness successfully released back into the wild - the first to have contact after release, and the first known to have cubs. The Adamsons kept their distance from the cubs but they got close enough to photograph them.

After Elsa’s death in January 1961, brought on by a disease from a tick bite, the Adamsons worked to avert the possible execution of the young cubs. Without their mother to feed and guide them, the cubs had become a nuisance, killing livestock and angering local farmers. To capture them was a challenge. George constructed three identical cage traps, and after much waiting the three were captured and transported to neighboring Tanzania where they were promised a home at a national park. In The Story of Elsa, a compilation of the books about Elsa, Joy Adamson wrote: "My heart was with them wherever they were. But it was also with these two lions here in front of us; and as I watched this beautiful pair, I realized how all the characteristics of our cubs were inherent in them. Indeed, in every lion I saw during our searches I recognized the intrinsic nature of Elsa, Jespah, Gopa and Little Elsa, the spirit of all the magnificent lions in Africa."[citation needed]

Using her own notes and George’s journals, Joy Adamson wrote Born Free to tell the lions' tale. She submitted it to a number of publishers before it was bought by Harvill Press, part of HarperCollins. Published in 1960, it became a bestseller, spending thirteen weeks at the top of The New York Times Best Seller list and nearly a year on the chart overall. The success of the book was due not just to the captivating story of Elsa, but to the dozens of photographs of her. Readers had pictures of many of the events of Elsa’s life leading up to her release. Subsequent books were also heavily illustrated.

Born Free received largely favorable reviews from the critics. Adamson worked closely with publishers in order to properly promote the book which contributed to the Adamsons' new-found international celebrity. Joy Adamson would spend the rest of her life raising money for wildlife, thanks to the popularity of Born Free. The book was followed by Living Free, which is about Elsa as a mother to her cubs, and Forever Free, which tells of the release of the cubs Jespah, Gopa and Little Elsa.

While Joy Adamson generously shared book proceeds with various conservation projects, she showed no such generosity with her husband, George, from whom she was ultimately separated.

The 1966 film Born Free, starring husband-and-wife actors Bill Travers and Virginia McKenna and filmed in the bush over the course of many months, was a worldwide hit. The stars got to know the real Adamsons, and the couples remained friends for life, working for wildlife causes. Travers and McKenna decided to do all of their own scenes with the lions in the film in order to recreate the close relationship that Joy and George Adamson had with Elsa. This was a serious commitment and risk on the actors’ part but one that made the film more realistic. The film, which went on to win two Academy Awards (both for music) is widely considered to be a family classic. Six years later, Susan Hampshire took over the role of Joy Adamson in Living Free, a film based on the third “Elsa book,” Forever Free. The theme of the film, "Born Free", which appeared on the film's soundtrack album, was also a popular hit.

Perhaps the most important aspect of the filming of Born Free was that some of the lions used for the film were freed as Elsa had been. This story was told in a documentary produced by Bill Travers titled The Lions Are Free..

In the 1960s, Joy Adamson lived at Elsamere on the shores of Lake Naivasha. Elsamere is now an Education Center and visitors to Kenya can stay there and visit local wildlife.