Davis was born on January 21, 1956, in Wareham, Massachusetts. Her mother, Lucille (née Cook; June 19, 1919 – November 15, 2001), was a teacher’s assistant, and her father, William F. Davis (November 7, 1913 – April 2, 2009), was a civil engineer and church deacon; her parents were both from small towns in Vermont. She has an older brother named Danforth (“Dan”).

In the television series The Exorcist (2016), based on the 1973 film of the same name, Davis took on the role of grown-up Regan MacNeil, who has renamed herself Angela Rance to find peace and anonymity from her ordeal as a child. The Exorcist was a success with critics and audiences. In 2017, Davis starred in the film adaptation Marjorie Prime, alongside Jon Hamm, playing the daughter of an 85-year old experiencing the first symptoms of Alzheimer’s disease, and appeared as the imaginary god of a heavyset 13-year-old girl in the comedy Don’t Talk to Irene. Vanity Fair felt that she “shine[d]” and stole “every scene” in Marjorie Prime, while Variety, on her role in Don’t Talk to Irene, remarked: “There’s no arguing the preternatural coolness of Geena Davis —a fact celebrated in self-conscious fashion by Don’t Talk to Irene, a familiar type of coming-of-age film whose most distinguishing feature is the presence of the actress”.

Davis began dating restaurateur Richard Emmolo in December 1977 and moved in with him a month later. The two married on March 25, 1981, but separated in February 1983 and divorced on June 27, 1984.

At an early age, she became interested in music. She learned piano and flute and played organ well enough as a teenager to serve as an organist at her Congregationalist church in Wareham. Davis attended Wareham High School and was an exchange student in Sandviken, Sweden, becoming fluent in Swedish. She attended New England College before earning a bachelor’s degree in drama from Boston University in 1979. Following her education, Davis served as a window mannequin for Ann Taylor until signing with New York’s Zoli modeling agency.

Davis was working as a model when she was cast by director Sydney Pollack in his film Tootsie (1982) as a soap opera actress whom she described as “someone who’s going to be in their underwear a lot of time”. The film was the second most profitable screen production of 1982, received ten Academy Awards nominations and is considered a cult classic. She next obtained the regular part of Wendy Killian in the television series Buffalo Bill, which aired from June 1983 to March 1984; she also had a writing credit in one episode. Despite the series’ eleven Emmy Awards nominations, the lukewarm ratings led to its cancellation after two seasons. At the time, Davis guest-starred in Knight Rider, Riptide, Family Ties and Remington Steele, and followed with a series of her own, Sara, which lasted 13 episodes. During this period, she landed an audition for the 1984 science fiction/action film The Terminator reading for the lead role of Sarah Connor, a part which eventually went to Linda Hamilton. In Fletch (1985), an action comedy, Davis appeared as the colleague of a Los Angeles Times undercover reporter trying to expose drug trafficking on the beaches of Los Angeles, opposite Chevy Chase. In 1985, she also starred in the horror comedy Transylvania 6-5000, as a nymphomaniac vampire alongside future husband Jeff Goldblum. They would reunite professionally in the sci-fi thriller The Fly (1986), loosely based on George Langelaan’s 1957 short story of the same name and in which Davis portrayed a science journalist and the love interest of an eccentric scientist. Caryn James, of The New York Times, found her to be “stiff” in The Fly, a film she considered “intense, all right, but not scary or sad, or even intentionally funny”. Nevertheless, it was a commercial success and helped to establish her as an actress. In 1987 she appeared with Goldblum again in the offbeat comedy Earth Girls Are Easy.

In 1985, she met her second husband, actor Jeff Goldblum, on the set of Transylvania 6-5000. The couple married on November 1, 1987 and appeared together in two more films: The Fly and Earth Girls Are Easy. Davis filed for divorce in October 1990, and it was finalized the following year.

In 1992, Davis starred alongside Madonna and Tom Hanks in A League of Their Own as a baseball player on an all-women’s team. It reached number one on the box-office, became the tenth highest-grossing film of the year in North America, and earned her a Best Actress Golden Globe Award nomination. She played a television reporter in the comedy Hero (also 1992), alongside Dustin Hoffman and Andy Garcia. While the film flopped at the box office, Roger Ebert felt that Davis was “bright and convincing as the reporter (her best line, after surviving the plane crash, is shouted through an ambulance door: “This is my story! I did the research!”)”.

After a five-month courtship, Davis married filmmaker Renny Harlin on September 18, 1993. He directed her in Cutthroat Island and The Long Kiss Goodnight. Davis filed for divorce on August 26, 1997, a day after her personal assistant gave birth to a child fathered by Harlin. The divorce became final in June 1998.

Davis teamed up with her then-husband, director Renny Harlin, for the films Cutthroat Island (1995) and The Long Kiss Goodnight (1996), with Harlin hoping that they would turn her into an action star. While The Long Kiss Goodnight managed to become a moderate success, Cutthroat Island flopped critically and commercially and was once listed as having the “largest box office loss” by Guinness World Records. The film is credited to be a contributing factor in the demise of Davis as a bankable star. She divorced Harlin in 1998 and took an “unusually long” two years off to reflect on her career, according to The New York Times. She appeared as Eleanor Little in the well-received family comedy Stuart Little (1999), a role she reprised in Stuart Little 2 (2002) and again in Stuart Little 3: Call of the Wild (2005).

In 1998, Davis started dating neurosurgeon Reza Jarrahy, and allegedly married him on September 1, 2001. They have three children: a daughter, Alizeh (born April 2002), and fraternal twin sons, Kaiis and Kian (born May 2004). In May 2018, Jarrahy filed for divorce from Davis; listing their date of separation as November 15, 2017. Davis responded by filing a petition in which she claimed that she and Jarrahy were never legally married.

In July 1999, Davis was one of 300 women who vied for a semifinals berth in the U.S. Olympic archery team to participate in the Sydney 2000 Summer Olympics. She placed 24th and did not qualify for the team, but participated as a wild-card entry in the Sydney International Golden Arrow competition. In August 1999 Davis stated that she was not an athlete growing up and that her introduction to archery was in 1997, two years before her tryouts.

In 2004, while watching children’s television programs and videos with her daughter, Davis noticed an imbalance in the ratio of male to female characters. Davis went on to sponsor the largest research project ever undertaken on gender in children’s entertainment (resulting in four discrete studies, including one on children’s television) at the Annenberg School for Communication at the University of Southern California. The study, directed by Stacy Smith, showed that there were nearly three males to every one female character in the nearly 400 G, PG, PG-13, and R-Rated movies the undergraduate team of Annenberg students analyzed. In 2005, Davis teamed up with the non-profit group, Dads and Daughters, to launch a venture dedicated to balancing the number of male and female characters in children’s television and movie programming.

Davis starred in the sitcom The Geena Davis Show, which aired for one season on ABC during the 2000–01 U.S. television season. She went on to star in the ABC television series Commander in Chief, portraying the first female president of the United States. While this role garnered her a Golden Globe for Best Actress in a Drama Series in 2006, the series was cancelled after its first season; Davis admitted she was “devastated” by its cancellation in a 2016 interview. “I still haven’t gotten over it. I really wanted it to work. It was on Tuesday nights opposite House, which wasn’t ideal. But we were the best new show that fall. Then, in January, we were opposite American Idol. They said, ‘The ratings are going to suffer, so we should take you off the air for the entire run of Idol, and bring it back in May. I put a lot of time and effort into getting it on another network, too, but it didn’t work”. She was also nominated for an Emmy Award and a SAG Award for Outstanding Female Actor in a Drama Series. She was awarded the 2006 Women in Film Lucy Award.

Davis launched the Geena Davis Institute on Gender in Media in 2007. The institute’s first focus is an on-the-ground program that works collaboratively with the entertainment industry to dramatically increase the presence of female characters in media aimed at children and to reduce stereotyping of females by the male-dominated industry. It seeks to address inequality in Hollywood. For her work in this field she received an honorary Doctor of Fine Arts degree from Bates College in May 2009 and the Academy’s Jean Hersholt Humanitarian Award, an Honorary Oscar, in 2019.

In 2011, Davis became one of a handful of celebrities attached to USAID and Ad Council’s FWD campaign, an awareness initiative tied to that year’s East Africa drought. She joined Uma Thurman, Chanel Iman and Josh Hartnett in television and internet ads to “forward the facts” about the crisis.

Following a long period of intermittent workload, Davis often ventured into television acting, and through her organization, the Geena Davis Institute on Gender in Media, saw her career expanded during the 2010s. In 2012, Davis starred as a psychiatrist in the miniseries Coma, based on the 1977 novel Coma by Robin Cook and the subsequent 1978 film. She played a powerful female movie executive in the critically acclaimed comedy In a World… (2013), the directorial debut of Lake Bell. Bell found Davis’s only dialogue to be her favorite in the film and called it her “soapbox moment”.

In 2014, Davis provided her voice for the English version of the Studio Ghibli animated film When Marnie Was There, as she was drawn to the film’s abundant stories and strong use of female characters. She played the recurring role of Dr. Nicole Herman, an attending fetal surgeon with a life-threatening brain tumor, during the 11th season of Grey’s Anatomy (2014–15). In 2015, Davis launched an annual film festival to be held in Bentonville, Arkansas, to highlight diversity in film, accepting films that prominently feature minorities and women in the cast and crew. The first Bentonville Film Festival took place from May 5–9, 2015. Davis appeared as the mother of a semi-famous television star in the comedy Me Him Her (2016).

By the mid and late 1990s, Davis’s film career had become less noteworthy and critical acclaim had waned. In a 2016 interview with Vulture, she recalled: “Film roles really did start to dry up when I got into my 40s. If you look at IMDb, up until that age, I made roughly one film a year. In my entire 40s, I made one movie, Stuart Little. I was getting offers, but for nothing meaty or interesting like in my 30s. I’d been completely ruined and spoiled. I mean, I got to play a pirate captain! I got to do every type of role, even if the movie failed.”

In 2018, Davis returned to Grey’s Anatomy, reprising the role of Dr. Nicole Herman in the show’s 14th season, and executive produced the documentary This Changes Everything, in which she was also interviewed about her experiences in the industry. The film premiered at the Toronto International Film Festival, where it was named first runner-up for the People’s Choice Award: Documentaries. In 2019, she joined the voice cast of She-Ra and the Princesses of Power as Huntara. Also in Netflix in 2019, she joined the cast of Glow as Sandy Devereaux St. Clair, a former showgirl turned entertainment director of the Fan-Tan Hotel and Casino.

Davis appeared as the girlfriend of a man who, dressed as a clown, robs a bank in midtown Manhattan, in the comedy Quick Change (1990), based on a book of the same name by Jay Cronley, and a remake of the 1985 French film Hold-Up starring Jean-Paul Belmondo. Despite modest box office returns for the film, the Chicago Tribune found the lead actors to be “funny and creative while keeping their characters life-size”. Davis next starred with Susan Sarandon in Ridley Scott’s road film Thelma & Louise (1991), playing friends who embark on a road trip with unforeseen consequences. A critical and commercial success, the film is considered a classic, as it influenced other films and artistic works and became a landmark feminist film. She received an Academy Award nomination for Best Actress for her role. The film also featured Brad Pitt in his breakout role as a drifter, and in his 2020 acceptance speech for Best Supporting Actor, he thanked director Ridley Scott and Geena Davis for “giving me my first shot.”