Lara Jean is an ordinary girl, but her fate changes when the 5 letters she wrote are sent. After finding out they were sent, she makes a contract with one of the boys who got the letter: Peter Kavinsky. After a while, they fall in love with each other, but Peter's ex-girlfriend lies to Lara Jean about Peter's return to her (his ex). But, in the end, they are together again.
Following her relationship with Peter Kavinsky becoming serious and official, Lara Jean firmly believes herself to be living the dream; Kitty reminds her that she is not in a movie, however. Later that night, she enjoys her first date with Peter, and things go well. The two promise not to break one another's hearts and they share a kiss.
She later receives a letter from John Ambrose McClaren — a former recipient of her letters — in which he reminisces upon the times they spent together when they were younger. Lara Jean is perplexed by the letter, initially believing her letter to be lost in the post, and is indecisive upon whether to reply. She eventually decides against replying to the letter, given her relationship with Peter. She decides to tell Peter about the letter the following day at school, and he questions if she replied, however, she reveals that she did not. Peter is taken aback by the whole situation, but brushes it off when the two are faced with the decision of where they will volunteer. Lara Jean reveals that she is applying for Belleview, and believes Peter to be doing the same, however, conflicts arise when Peter reveals that he will be volunteering at Oakwood instead.
Lara Jean becomes instant friends with one of the residents at Belleview, Stormy. The two talk and Stormy gives her a tour of the residents' home, enticing her to skip the tour by the management. When she eventually does go to sign in, she is shocked and confused to find that John is also volunteering at Belleview. Embarrassed, she asks John for the letter back, and he agrees, on the condition that she return the letter to him upon completion of reading.
Lara Jean and kitty talk about the possibility of their father dating their neighbor, Mrs. Rothschild. Lara Jean believes the relationship will not progress any further, however, Kitty intervenes and sends Mrs. Rothschild a Valentines on their father's behalf.
On Valentines Day, Lara Jean expects Peter to have organised the choir to sing to her, given this is what he did for Gen the previous year. She is disappointed when he doesn't, however, but she forgives him when he gives her an expensive necklace shortly after, and reads her a poem. The necklace was from Peter’s mom’s store and it was something Lara Jean had wanted for a while
The relationship between Lara Jean and John becomes increasingly complex and tense when they must work together to clean out a room for an indoor-outdoor garden party. John hands her the letter she wrote to him and Lara Jean leaves to read the contents. She becomes emotional at reading the letter and Stormy invites her inside her room where the two talk. When Lara Jean recites the poem to Stormy that Peter wrote to her, she is disappointed to find out that the poem is actually written by Edgar Allen Poe, not Peter. Lara Jean becomes increasingly concerned for the relationship she shares with Peter, questioning if he did things differently with Gen.
At a party later, she hangs out with Lucas and tells him that she thinks that she needs a break from being Peter's girlfriend. Peter realizes that Lara Jean is not enjoying the party, and suggests that the two head out. She agrees, and Peter drives her home. He begins making out with her, and she sternly remarks that she doesn't want to have sex with him in his car. Lara Jean questions Peter about the poem, and Peter remarks that he never claimed to have written the poem but, nevertheless, everything in the poem is a true reflection of the love he feels for Lara. Although he never said that he wrote it, it was very clear that he didn’t put the amount effort that Lara Jean expected. It made her realize that she was doing a lot of the heavy lifting in the relationship and she was putting the most effort, meanwhile Peter just wanted to have fun. Not convinced by this, Lara Jean asks if Peter misses sex, particularly with Gen, however, he replies that he doesn't.
She later makes small talk with John at Belleview's bingo game. John questions if Peter is still with Gen, and Lara Jean tells him that he isn't, but decides against telling John that she and Peter are dating. John asks for Lara Jean to return the letter, however she remarks that she has no plans to return the letter, effectively ending their agreement.
Lara Jean and Peter have more conflicts in their relationship when Lara Jean finds out that he and Gen have been spotted together. The situation is cleared up, however, when Gen reveals that her parents are divorcing and Peter was helping her get through it as a friend. so This brings not only Peter and Lara Jean closer but repairs the relationship between Gen and Lara Jean to some extent.
At the Belleview ball shortly after, John and Lara Jean dance, and eventually kiss. She quickly realizes that she does not want to be with John, and leaves the party to find Peter. Peter meets her on the doorstep, however, and the two repair their relationship; they kiss shortly after. Lara Jean realizes that the perfect relationship doesn't exist and, if she wants to be happy, she must risk it all.
Lara Jean has long dark hair and dark eyes. Although she believes that Margot looks the most like her mother, she actually resembles her mother the most out of her sisters. Therefore, she looks more Korean than Caucasian.
In the movie, she usually wears her hair in a ponytail but stops doing so by the end of the first movie, when Peter tells her he prefers it when her hair is down.
|“|| I have spread my dreams under your feet;|
Tread softly because you tread on my dreams.
—W. B. Yeats, Always and Forever, Lara Jean (Lara Jean's yearbook quote)
Lara Jean is generally considered a nice, quirky and shy girl and who enjoys scrapbooking, fashion, especially Korean and vintage clothing, and baking. She is said to have decent grades. She is extremely attached to her sisters Margot and Kitty and has a good relationship with her father. She misses her mother Eve Song but also wants her father to remarry, which he does in Always and Forever, Lara Jean.
She is also described as "a girl that falls in love easily", referring to how she tends to have crushes easier than other people might and is often called "quirky" by Peter Kavinsky.
Lara Jean loves her father a lot. She understands that sometimes it's hard for him to understand her feelings and problems completely and that he tries his best to support her nonetheless. As shown in P.S. I Still Love You, she is afraid of disappointing her father, since his opinion of her means very much to her.
Margot is Lara Jean's older sister. It's mentioned that they used to fight a lot when their mother was still alive but became very close to each other after her death. They are protective of each other and comfort each other when one of them is sad. The relationship is strained, however, when it is revealed that Margot's boyfriend is the recipient of one of Lara Jean's letters, however the two are able to repair their relationship.
Kitty is Lara Jean's little sister. They love and care for each other but tend to have small fights quite often, which eventually resolve. Lara Jean isn't as close to her as to Margot, nevertheless, she loves her equally.
Lara Jean likes Trina and supports her relationship with her father. When her father and Trina marry in Always and Forever, Lara Jean, making Trina her step-mother, she is happy that her father has met a woman that can make him completely happy again.
Lara Jean had feelings for Peter since middle school, although she eventually gives up on him and tries to completely stop loving him by writing him a letter. After a series of unfortunate events, they end up fake-dating, which was Peter's attempt to get his old girlfriend back. When she realizes that she had fallen for him again, she tries to suppress her feelings for him at first but gives in when Peter confesses to her. He ends up being her boyfriend.
Lara Jean and John Ambrose McClaren are childhood friends who got separated after John's family moved away. After reconnecting through Lara Jean's letter, they begin to develop romantic feelings for each other, which make Lara Jean wonder how it would be to be in a relationship with John instead of Peter. Ultimately, she ends up choosing Peter over John.
Josh is Lara Jean's childhood friend and Margot's ex-boyfriend. After Margot and he break up at the beginning of To All the Boys I've Loved Before, Lara Jean is afraid that the feelings she used to have for him until 9th grade might surface again and when her letters get sent out, she starts a fake relationship with Peter to conceal her feelings for Josh.
Chris and Lara Jean are friends since their childhood, although Lara Jean used to be closer to Genevieve than to Chris in the past. Their interests were similar until high school but then Chris started going out on parties often, which Lara Jean doesn't like very much, but accepts. They are still best friends, even if they're not as close anymore.
Lara Jean becomes friends with Stormy upon beginning her volunteering at Belleview retirement home. The two instantly connect, and a close relationship forms between the two. Stormy gives her relationship advice on numerous occasions, and encourages her to fix things with Peter despite having kissed John Ambrose.
Genevieve and Lara Jean used to be childhood friends until Genevieve cut ties with her before high school. Lara Jean never understood why they stopped being friends but accepted it. In P.S. I Still Love You it is revealed that Genevieve saw Lara Jean kissing Peter at the gathering at John's house in seventh grade, making her feel betrayed by Lara Jean, who knew that Genevieve liked Peter and that Genevieve didn't consider them friends from that point on. However, at the end of the book, it is shown that Genevieve, just like Lara Jean, put her friendship bracelet into the time capsule at the end of middle school, it being the thing dearest to her at that time.
- Lara Jean's character is based on Beth from Louisa May Alcott's Little Women.
- Lara Jean's love for baking and cooking originated from Jenny Han's love for said and because she believes that "food connects people". 
- Peter was Lara Jean's first kiss.
- Peter and Lara Jean's song is Let's Stay Together by Al Green.
- Her alternative yearbook quote was "Without you, today's emotions would be the scurf of yesterday's" (Hipolito, Amélie).
- Lara Jean's university choices were UVA, William & Mary, James Madison, University of Richmond and the University of North Carolina at Chapel Hill.
- Lara Jean's birthday is in May.
- Lara Jean is a Hufflepuff.
- Lara Jean's dream man is Gilbert Blythe from 'Anne of Green Gables'.
- In the movie, it is shown that her address is 9147 Jefferson Street, Greenpoint, OR 97501.
- In the movie, Lara Jean is left-handed.