Born in New York City on 14 April 1996, to Kim, a talent manager, and Michael Breslin, a telecommunications expert and consultant, Abigail Kathleen Breslin, one of the most sought-after actors of her generation, began acting in commercials when she was only three years old. For the purpose of pursuing her career in acting, she was primarily homeschooled with tutors even on film sets during her early acting days, but later she combined her acting career with a serious commitment to academics. She earned an Associate Degree from Carl Sandburg College, and then graduated from Knox College, with a focus on International Relations. After that, she also graduated from the prestigious Elliott School of International Affairs, under George Washington University.

Her first acting role, at the age of six, was in the science fiction thriller film Signs (2002), directed by M. Night Shyamalan, in which she played the role of Bo Hess, the daughter of the main character, and was praised by critics for her incredible and terrifically natural, nuanced performance in the film. After that, she appeared in the romantic comedy film Raising Sun (2004), in which she and her brother Spencer played siblings, and in Chestnut: Hero of Central Park (2004), depicting the story of two sisters and a puppy at an orphanage. The same year, she also had a small role as an orphan named Carolina in The Princess Diaries 2: Royal Engagement (2004), and in the independent film Keane (2004), in which she played Kira Bedik, a young girl who reminds the mentally disturbed protagonist William Keane of his missing, abducted daughter.

In 2006, Abigail appeared in the American drama film The Ultimate Gift (2006), playing the role of Emily Rose, an outspoken girl suffering from leukaemia, and encouraging a romance between Jason, the male lead of the film, and her mother. But her big break came when she appeared as Olive Hoover, an ambitious beauty pageant contestant, the youngest in a dysfunctional family on a road trip, in the critically acclaimed comedy-drama Little Miss Sunshine (2006), the irreverent, antic comedy which created a sensation at the Sundance Film Festival. Her performance in the critically and commercially film was highly praised, and she won the Best Actress Award at the Tokyo International Film Festival and also earned nominations for an Academy Award, as well as BAFTA and SAG Awards for Best Supporting Actress.

After that, Abigail appeared in the romantic comedy film No Reservations (2007), playing the niece of master chef Kate Armstrong, played by Catherine Zeta-Jones, which garnered mostly negative reviews but was successful commercially, grossing $92 million worldwide, while the famous film critic, Roger Ebert commented that Abigail Breslin has the stuff to emerge as a three-dimensional kid. The next year, she played the role of Maya Hayes, the daughter of a recently divorced father, eager to know about her father's life before his marriage, in Adam Brook’s Definitely, Maybe (2008), which garnered generally favourable reviews, with Steven Rea of The Philadelphia Inquirer daily newspaper depicting Abigail as alarmingly cute, backing the cuteness up with serious acting instinct. The same year, she starred with Jodie Foster in Nim’s Island (2008) as Nim Rusoe, a young girl on a remote tropical island, trying to overcome the fear of losing her father, and seeking help from a San Franciscan author, suffering from anxiety disorders.

The same year, Abigail also played the title role in Kit Kittredge: An American Girl (2008), a high-profile project, based on the American Girl line of dolls, books, and accessories of which Breslin is a fan, and carried the production on her shoulders with unflagging grace, at the tender age of twelve. For her performance in the film, Abigail Breslin won the Critics Choice Award for Best Young Actress, and was also nominated for an Academy and BAFTA Award for Best Actress in a Supporting Role.

In 2009, Breslin starred with Cameron Diaz in My Sister's Keeper (2009), playing the role of Anna Fitzgerald, a young girl who was conceived to be a donor for her sister, Kate, who suffers from leukaemia, and also starred with Emma Stone, playing her younger sister, Little Rock, a sweet 12-year-old who sadly had to grow up quickly in a world filled with zombies, in the horror comedy Zombieland (2009), depicting the story of four survivors of a Zombie apocalypse, making their way on an extended cross-country road trip to find a sanctuary free from an evil virus that turns people into zombies. Later, Breslin reprised her role in Zombieland: Double Tap (2019), featuring four Academy Award nominees and winners, which apart from Abigail Breslin also included Jessie Eisenberg, Emma Stone and Woody Harrelson.

Her films in 2013 include the thriller The Call (2013), playing the problematic role of Casey Welson in which she was forced to cry and scream nearly continuously, followed by the Canadian supernatural horror film Haunter (2013), portraying the role of Lisa, a ghost who bonds with a future girl living in her house to stop an evil killing spirit with the help of his many victims, and the space science-fiction film Ender’s Game (2013). Next year, she appeared as Sandra Anderson in the crime drama Perfect Sisters (2014) Another important film of Breslin during the 2010s is the zombie horror film Maggie (2015), in which she played the titular Maggie, a teenage girl from a small town in the Midwest, who becomes infected by a disease that slowly turns her into a zombie, spending the last moments with her family, particularly her father, played by Arnold Schwarzenegger

Abigail Breslin's transition to adult roles happened gradually as she grew, but the horror film Final Girl (2015), in which she appeared as Veronica, whom a male teacher taught how a young woman can become a complete weapon, marked her full-fledged adult role. Her subsequent important films during the 2020s include the crime drama film Stillwater (2021), American period drama film Miranda’s Victim (2023), and the spy thriller Classified (2024).

In April 2017, Abigail Breslin confessed that she was once raped by an ex-boyfriend, but she did not dare to report the matter to the police, apprehending that they would not believe her story. But the shocking incident completely shattered her, and she was diagnosed with post-traumatic stress disorder that developed from experiencing that traumatic event. During that time, her long-time best friend, Ira Kunyansky, was by her side, and helped to keep her sane. However, despite involvement in the entertainment industry since childhood, her best friend was not part of the Hollywood world, and had no idea who she was when they first met. Nevertheless, according to their social media profiles, she started dating Ira Kunyansky in April 2017, and got engaged on a beach in Malibu, California, in February 2022. Finally, the couple got married on 18 June 2023, at the Hummingbird Nest wedding venue in the Santa Susana Mountains, just north of Los Angeles.