Lively was born on August 25, 1987, in the Tarzana neighborhood of Los Angeles. She is the daughter of Ernie Lively (né Ernest Wilson Brown, Jr.), an actor, and his wife, Elaine (née McAlpin), who worked as a talent scout. She was named after her grandmother's brother. She has an older brother, Eric, two half-sisters, Lori and Robyn, and a half-brother, Jason. Both of her parents and all of her siblings are, or have been, in the entertainment industry.
Lively is of English, Irish and German ancestry. She also claims to be of Cherokee descent, but no proof has been provided to substantiate this.
During Lively's childhood, her parents took her with them to acting classes that they taught because they did not want to leave her with a babysitter. Lively said that watching her parents teach acting classes helped her learn the "drills" of acting and gain confidence as she got older. She was initially not particularly interested in acting, and wanted to attend Stanford University. During the summer between her junior and senior years of high school, her brother Eric asked his agent to send her on a few auditions over a period of a few months. From these auditions, she was cast as Bridget for The Sisterhood of the Traveling Pants. Lively filmed her scenes in that film between her junior and senior years at Burbank High School. While at Burbank, Lively served as senior class president, a cheerleader, and a member of the championship choir.
Lively began her acting career at age 10, when she appeared in the 1998 film Sandman, which was directed by Lively's father. She describes her role as a "bit part". She appeared in the film adaptation of the novel of the same name, The Sisterhood of the Traveling Pants, in 2005, as Bridget, one of the four female leads. Lively's performance in the film earned her a nomination for a Teen Choice Award for "Choice Movie Breakout – Female. In 2006, Lively co-starred with Justin Long in Accepted, and Lively had minor roles in the horror film, Simon Says. While Accepted was not well received by critics, Lively's performance was, earning her a 'Breakthrough Award' from Hollywood Life. In 2007, she played one of the two title characters in Elvis and Anabelle as Anabelle, a bulimic girl who hoped to win a beauty pageant. Lively said of getting into character for the role that she had 'shed serious weight' for her height. Lively stated that that process was difficult for her because food is "the No. 1 love of my life." MovieLine.com praised her performance in the film and credited it as having been her "breakthrough role".
Lively was cast in The CW's series Gossip Girl, based on the book series of the same name by Cecily von Ziegesar, which premiered in September 2007. Already having deferred college for a year, Lively intended to turn the role down and become a student, but was told that she could attend college part-time while filming the show (she later said "This is advice to anyone: when they say, 'We promise, but we can’t put it in writing,' there’s a reason they can’t put it in writing"). She played the role of Serena van der Woodsen in the teen drama until 2012 when the show ended. Her first magazine cover was the November 2007 issue of Cosmo Girl, where she discussed her time in high school and her career prior to Gossip Girl. In 2008 Lively reprised her role as Bridget in the sequel The Sisterhood of the Traveling Pants 2. Similarly to the first film, Lively's performance was positively received by critics. As of November 2008, the film had earned over $44 million at the box office. In 2009 Lively appeared as Gabrielle DiMarco, a minor role in the romantic comedy New York, I Love You, a sequel to the 2006 film Paris, je t'aime. Despite positive critical reception, the film did not fare well at the box office.
One of Lively's most acclaimed roles to date is her supporting role as the younger version of the title character in The Private Lives of Pippa Lee (2009). Paul Byrnes, of the Brisbane Times, described Lively's performance in the film as "sensational". In October 2009 Lively began filming her scenes for her role as Kristina "Kris" Coughlin in the 2010 film The Town, based on Chuck Hogan's novel Prince of Thieves. The film, which was directed by and starred Ben Affleck, was released in the United States on September 17, 2010. Lively played Carol Ferris, the female lead and love interest of Hal Jordan in the superhero film Green Lantern, which was released in June 2011. The film grossed a worldwide total of $219,851,172. but was considered a summer disappointment as it "failed to perform to expectations" even though it grossed more than its budget. Lively appeared in the music video for The Lonely Island's "I Just Had Sex" together with Jessica Alba in December 2010.
In 2011 she was featured in the annual TIME magazine 100 influential people. Additionally, AskMen.com named her the most desirable woman of 2011 and People magazine named her one of 2012's Most Beautiful at Every Age. In 2012 she starred in Oliver Stone's Savages alongside Taylor Kitsch, Aaron Johnson, Salma Hayek, and John Travolta. Lively replaced Jennifer Lawrence as Ophelia, after the latter dropped out to do The Hunger Games instead. HitFix film critic Drew McWeeny praised Lively's performance, which he described as "smart and sad precisely because she plays O as such a broken, needy little soul". The same year she was selected as the face of the new Gucci fragrance, Gucci Premiere. She appeared in a short film ad directed by Nicolas Winding Refn for the fragrance. In October 2013 Lively was named the new face of L'Oreal, marking her first major makeup campaign. Most recently Lively starred in the film The Age of Adaline (2015), opposite Michiel Huisman and Harrison Ford, playing a woman who "stops aging after recovering from a near-fatal accident." The film was a modest commercial success, grossing $54.5 million from a production budget of $25–30 million. In 2016 Lively starred in the survival horror film The Shallows. It received mostly positive reviews and Lively's performance was praised by critics.
In 2017, she was announced to play the female lead of the film adapation of the Mark Burnell novel The Rhythm Section, produced by Barbara Broccoli and Michael G. Wilson, and directed by Reed Morano.
Lively describes herself as a "foodie and cook," and has said Martha Stewart is her "idol;" she is also a fan of Nigella Lawson's work. In 2008 Lively baked a cake with Stewart during an episode of The Martha Stewart Show. In 2009 Lively stated that she "hoped one day to have an interior decorating company," citing her love for antiques and fascination with "colors and textures and layering things." In 2010 she attended a tailor-made workshop at Le Cordon Bleu in Paris, and has spoken of her desire to return to the culinary school for further instruction.
Also in 2010 Lively spent an evening working as a pastry chef at the renowned Per Se in New York City. She has remarked that, when travelling, she always takes cookery classes to immerse herself in the local culture. In 2010 and again in 2011, Lively spoke publicly of her desire to become a restaurateur. In 2011 she created a s'mores cupcake to be sold at Sprinkles bakeries. In 2012 Lively's wedding reception was featured in Martha Stewart Weddings; food photography was the focal point of the picture spread. In 2013 she appeared in Elle Decor to recount her experiences designing a custom La Cornue oven for her newly purchased Bedford home. In 2013 she filmed a cooking segment for Vogue's website, demonstrating how to make a brie pastry. In 2014 she launched Preserve, a digital magazine and e-commerce website with hand-made one-of-a-kind items all selected by Lively; on October 9, 2015, Lively closed the site, stating that it had been launched before it was ready, and that she plans to rebuild and relaunch it properly.
During the 2008 United States presidential election, Lively expressed her support for Barack Obama. Lively and Penn Badgley appeared in a pro-Obama commercial, as part of MoveOn.org's Youth Vote program. The commercial, directed by Doug Liman, aired during Gossip Girl on the CW, MTV and Comedy Central. In 2013 she appeared in a video clip for Gucci's "Chime for Change" campaign that aims to raise funds and awareness of women's issues in the areas of education, health, and justice.
Lively met actor Ryan Reynolds while filming Green Lantern in early 2010, and the two began dating in October 2011. They bought a home in Bedford, New York in June 2012, and got married on September 9, 2012, at Boone Hall in Mount Pleasant, South Carolina. They have two daughters: James and Ines.