Brooke Penelope Davis was born in New Brunswick County Hospital in Tree Hill, North Carolina to parents Richard Edgar Davis and Victoria Anne Davis (née Montgomery) on March 4, 1988. She has been Tree Hill's It Girl and has been described as the wealthy, popular and promiscuous captain of the cheerleading squad of Tree Hill High. The lack of authority in her life caused Brooke's high school years to be full of parties, drinking, and promiscuity. She has also formed many close friendships; Peyton Sawyer, her best friend since the age of nine, former roommates Haley James Scott, and her husband Nathan Scott, Rachel Gatina, Mouth McFadden and Millicent Huxtable.

Karen Roe, Lucas's mother was Brooke's only mother figure growing up after she moved in with her when her parents left Tree Hill. Over the years she has grown to become more mature, independent and successful thanks notably to her relationship with Lucas Scott. Although the two broke up due to his and her "best friend" Peyton's betrayals. Brooke later forgives both of them, and remains close with the two.

Brooke's relationships with her mother and foster daughter are shown to play a significant role in her character development. In the fifth and sixth seasons, her long-estranged mother Victoria returns, but remains cold and detached. Eventually, Brooke is motivated to become a good mother herself, which prompts her to take in a teenage foster child named Samantha. Though Sam is initially resistant, the two eventually bond as Brooke proves herself to be a dedicated parent.

Brooke is a successful fashion designer of her company, Clothes Over Bros. Brooke finds it hard to love again after being betrayed twice by Lucas and Peyton, but later falls for Julian Baker. Brooke has learned she cannot have children, but embraces the role of godmother to Jamie Scott and Sawyer Brooke Scott.

Brooke Davis is introduced in episode two and takes a liking to Lucas Scott, and starts hitting on him in her usual way. But Lucas is interested in her best friend Peyton whom he has liked for years. One night, after Peyton is drugged at a party, Brooke calls Lucas for help. And while caring for a drugged-out Peyton, Lucas sees a whole new side of Brooke, a side he likes. Lucas and Brooke eventually start dating. After realising he still has feelings for Peyton, Lucas starts an secret romance with Peyton behind Brooke's back. When Brooke finds out she ends her relationships with both of them. Brooke has a pregnancy scare following their break up. Lucas said he would be there for her but she rejected him. During an argument she receives the results. She then lies and pretends to be pregnant when it turns out she isn't to punish him for cheating on her with her best friend, Peyton. Later she admits she lied. Towards the end of the season Brooke and Peyton start to become friends again after standing united against Nicki. In the beginning of the season two, Brooke father losing his Job, causing them to have to sell their stuff and temporarily become poor, causing her to grow up. Still hurt over the way things ended with Lucas, she begins a relationship with her neighbor, Felix, which is simply "Friends With Benefits". Later, Mouth tells Brooke that he is in love with her too, but she thinks of him as a 'little brother'. She then begins to date Felix after he promises he won't break her heart as Lucas did. Brooke then decides to run for Student Council President, against students who are much more studious, hard working and experienced than her. Brooke doesn't back down even in the face of dirty politics by her rival, Erica Marsh, and wins the post of Student Council President after Mouth delivers a touching recommendation speech to a packed auditorium for her. She quickly befriends Mouth once again, as well as Erica. Brooke finds out that her parents are moving to California as her father has got a new job. Brooke is shocked when she finds out that Lucas has convinced Brooke's parents to let her stay with Karen, in Lucas' room, until the Summer, since Lucas is living with Dan. Brooke finds out that it was Felix who spray-painted the word 'DYKE' on Peyton's locker and immediately breaks up with him. Sexual tension rising between Brooke and Lucas. After discovering pictures of Peyton, Brooke thinks Lucas is still pining over Peyton and decides that she wants to be friends. When Brooke is about to leave for California for the summer, Lucas finally tells her how he feels. She is stunned and at the same time shattered. She leaves in a Taxi in tears.

Brooke returns from vacation but is worried about getting her heart broken again so only agrees that they can date if they do it non-exclusively and pretends that she spent her summer with lots of other guys, when she actually was writing letter to Lucas, daily, letters she didn't send. Lucas refuses to date anybody else during this time. At the fantasy boy draft, as a way to get back at Rachel she chooses Chris Keller, leaving Lucas angry at her. Feeling she has no hope with Lucas, she sleeps with Chris. Lucas is furious at Brooke leaving her heartbroken. She then starts her own clothing line "Clothes Over Bros". She later gives Lucas the 82 letters she wrote to him whilst on vacation, he forgives and the two begin dating, officially. Brooke decides to make Karen her wedding dress. After the school shooting occurs, Brooke helps Lucas and Karen pick up the pieces of their lives. Brooke then helps Nathan and Haley with their second wedding, becoming their Maid of Honor and maker of the wedding dress. However when Peyton reveals to Brooke that she has feelings for Lucas, yet again, at Nathan and Haley's rehearsal dinner, it brings back the 'love triangle', Brooke is enraged once again, and promptly ends her friendship with a teary-eyed Peyton. During a dance with Lucas at Nathan and Haley's wedding, he accidentally lets it slip that Peyton kissed him during the school shooting because he thinks she already knows. Brooke is enraged at first, and they have a huge fight during which she tells him that he never 'let her all the way in'.

Brooke decides she needs time to herself. She breaks up with Lucas but admits she will always love him and later moves in with Rachel. Pro-Life advocates, who call themselves the 'Clean Teens,' specifically Shelly, pressure Brooke to not terminate her pregnancy. It is revealed that Brooke was covering for Haley. Brooke later begins dating a man named Nick whom Rachel set her up with online, but he is revealed to be the new English teacher at Tree Hill High. However, they continue dating in secret. Rachel finally finds out, and tells Brooke that Nick hit on her. Brooke confronts him, he denies it and she breaks off her friendship with Rachel. She later sees he is cheating on her with one of her models, breaks things off with him and fixes things with Rachel. Brooke realizes that she still is in love with Lucas. Brooke asks Lucas to be her date for the end of the season basketball banquet. Later that night, Brooke tells Lucas it was a mistake and he heads home. After the state championship game, she encourages him to go with Peyton. Rachel then pretends to need Haley's tutoring so that they can steal the answers to a Calculus test for Brooke who is failing it but they get caught and pretend to have joined the Clean Teens as an alibi. There she meets Chase. During a class assignment, Brooke reveals to Chase that she cheated on the Calculus test. She also says she thinks she isn't pretty enough or talented enough for him, due to her relationship with Lucas. He tells her that she is good enough, and all she needs to do is to stop lying and be herself. They kiss and begin a new relationship together. The next week Chase and Brooke attend a party at Nathan's house. A tape entitled "Nathan Scores" is played which shows Brooke and Nathan having drunken sex. Brooke is punched by Peyton. Peyton is angry that Brooke completely cut her out of her life for being honest about her feelings for Lucas, when she felt Brooke was never honest with her. Peyton takes a black light marker and writes "whore" on Brooke's dress. Brooke feels it means Peyton still cares. After hearing that Peyton isn't going to prom, she suspects something is wrong and goes to her house. Brooke makes her way down to Peyton's basement where Derek knocks her out. Derek plans to kill her to show Peyton how much he loves her. Peyton convinces him to let her do it, but instead stabs him. Untied, Peyton runs to her room. Brooke unties herself and the two stand together against Derek. There, they rekindle their friendship. They go to prom together where Brooke is elected Prom Queen. Brooke and Chase get back together. Now that Brooke and Chase are dating again, they have sex at the graduation party. Lucas and Brooke share a special moment together as he confides in her with his book. She also becomes the godmother to Haley and Nathan's newborn son, James Lucas Scott. Brooke and Peyton prepare to spend the summer in LA, with her parents.

Three years in the future, she meets Lucas in NYC and has drinks with him. He shows her his engagement ring for Peyton and tells Brooke how Peyton turned down his proposal, which shocks Brooke. When she tries on the ring, everyone believes that they are engaged. They get free drinks and even a romantic horse-drawn carriage ride because of this. When they arrive at Lucas' hotel room, after Lucas and Peyton had broken up, he kisses her in a drunken stupor and she pulls away as he is still pining over Peyton, despite still having feelings for him. She leaves him with a few words of wisdom, telling him to finish his book. Brooke mentions that Lucas will probably not see her for a while. Her last words to him are "Lucas Scott is going to change the world someday and he doesn't even know it yet..." Giving him one last kiss, Brooke heads for the door, not to be seen for another three years.(502) Victoria later questions Brooke and Lucas's engagement. Brooke tells her Lucas was the one boy she would have lost everything to be with, and then accepts her mother's offer to expand her clothing line, wanting to get lost into work to cure her broken heart of Lucas.

Having become a multi-million dollar household name, Brooke runs her clothing line, magazine and channel. Becoming fed up with her fake celebrity life, she goes back to Tree Hill, after a distraught call from Peyton Sawyer. There she becomes a "fill in nanny" for Jamie and buys out Karen's Café in order to run her fashion business from her hometown, Tree Hill. Also, eagerly wanting to live in Tree Hill, she spontaneously buys a home (furniture and all) and invites Peyton to live with her. However, the CEO of her company, who also turns out to be her mother, Victoria, is not happy at all about Brooke's choice to stay in Tree Hill, and arrives unexpected to her new house to take Brooke back to New York.

Brooke and Victoria "bond" over the store opening, but she is oblivious that Victoria is running around insulting all of her friends. The store's opening is both a social success and a commercial failure, leading her mother to tear her down. She then reaches the breaking point after her mother attacks Peyton and rejects her daughterly love confession, beginning to rule her company her way and refusing to consider Victoria her mother any longer.. Brooke considers dating Owen, a bartender, and sets Mouth up on a blind date with Milicent. She also tells Peyton to go after Lucas because they are meant to be and comforts her after she finds out he proposed to Lindsey. She uses her naked-in-the-back-of-the-car trick on Owen and successfully gets his attention but then refuses to sleep with him. Brooke then slowly becomes friends with Lindsey but after they get stuck in the library with Haley, Peyton and Mia, Peyton tells her that she's her best friend and will always be, stopping the awkwardness. She travels to New York with Owen after she challenges him since he thinks she does nothing for her job. She shows him a space she bought to expand and they find Rachel, overdosed on drugs. Feeling guilty for firing her earlier, Brooke takes Rachel back to Tree Hill with her so she can live in Brooke's big house with her and Peyton. She attends Lucas and Lindsey's joint bachelor/bachelorette party with Owen, who brings along a surprise guest Chase, whom she had unknowingly set Peyton up with. She finally fires Victoria from the company after she scares Rachel off for monetary purposes. She tells Peyton and Lucas that she came back to Tree Hill to have a baby, because there was a void in her heart only having a family could fill. Due to this decision Brooke gets interviewed by a woman from an adoption agency who Brooke finds out has spoken to Victoria. Because of her young age, busy life and party past, Brooke is turned down. Owen then immediately ends his potential relationship with Brooke, after finding out she wants a baby, calling her selfish. However, she gets to have a baby, as she gains momentary custody of Angie who is there to get her heart operated on and finds it immediately challenging, but finds comfort and help in the form of Peyton and Lucas Brooke is terrified and distraught over the possibility of Angie not making it through her surgery, but Angie comes out perfectly and everything in Brooke's world calms down. She then has to return Angie early making her distraught but strengthening her friendship with Lucas. In the season finale, Lucas calls someone asking that someone if she wants to get married at Las Vegas—the someone could be Lindsey, Peyton or Brooke (it turns out he called Peyton).