Joan Molinsky was born in New York City, the daughter of Russian immigrants. She began attending college in Connecticut in 1950, completing her education in 1954 in New York, ultimately receiving a bachelor of arts in English literature and anthropology. After graduation, Molinsky took a series of jobs while pursuing work in show business. It was around this time that she adopted the stage name Joan Rivers, based on her the name of the agent who advised the change. She married for the first time in 1955, but the marriage was annulled six months later.
Rivers made her first foray into show business in the late 1950s, when she appeared in a play that ran for six weeks. She next performed in Chicago at Second City, where she made her first effort at comedy. She continued performing comedy through the 1960s, making her first television appearance on The Tonight Show in 1965. That same year she found work on the television series Candid Camera, where she wrote gags and acted as the bait to lure in unwitting participants, as well as making her first feature film appearance. She also appeared on The Ed Sullivan Show and briefly hosted her own talk show, as well as releasing two comedy albums. 1965 also witnessed her second marriage, this time to Edgar Rosenberg, a television producer. Their daughter, Melissa, was born in 1968. Rivers continued to be active on the television circuit into the 1970s, appearing on The Carol Burnett Show and Hollywood Squares, as well as narrating animated segments for The Electric Company. She wrote her first movie, a made-for-TV film entitled The Girl Most Likely To..., in 1973, and made her directing debut in 1978 with the film Rabbit Test, which she also wrote.
In the 1980s she continued to develop her comedy, headlining on Las Vegas stages and making frequent appearances on the Tonight Show at the behest of her close friend and mentor Johnny Carson. By 1983 she had become a regular guest host. During this year she also hosted Saturday Night Live for the first time. She released a third comedy album around this time, which earned her a Grammy nomination. In 1984 she published a comical faux-memoir that was met with some acclaim, though attempts to follow up the success of the book with a television special flopped. This was followed by a very public falling out with Carson after she was given a talk show, The Late Show Starring Joan Rivers, that competed with Carson's own show. Her involvement with the show only lasted a year, with her and her husband being fired as star and producer, respectively, after she protested plans for his removal as producer. Her husband committed suicide three months later. Two years later she returned to talk shows with The Joan Rivers Show, which proved to be a success, lasting for five years and earning Rivers an Emmy. In 1994 she and her daughter hosted the pre-show for the Golden Globe Awards. She continued to host pre-awards shows for several years, for which she became well known. Beginning in 2004 she made three appearances in the television series Nip/Tuck. She also created her own line of jewelry, which she sold on home shopping channels. She also began making frequent appearances on the panel show 8 out of 10 Cats. In 2004 she appeared on the children's television series Dave the Barbarian as the evil Queen Zonthara, the mother to her real-life daughter's Princess Irmaplotz. In 2006 she appeared on the animated television series Drawn Together. In 2007 she began work on a play, as well as appearing in the Royal Variety Show. 2008 saw appearances on Big Brother: Celebrity Hijack and Celebrity Family Feud. In 2009 she participated in Celebrity Apprentice along with her daughter. While she briefly walked off the show following Melissa's elimination, she returned and eventually won. In 2009 she was the target of a Comedy Central roast, and starred in the reality TV series How'd You Get So Rich?
A documentary about her, Joan Rivers: A Piece of Work, premiered in 2010. In 2011 she and her daughter began work on the television series Joan & Melissa: Joan Knows Best, which has been renewed for a new season.