Bette is introduced as an affluent, Ivy League-educated lesbian of African-American and Caucasian heritage. She grew up in Philadelphia and was an art history major at Yale, where she had sex with a gay man (Coleman) who at the time was her boyfriend, but she realized she had no interest in men through her crush on her art history professor named Danica Palmer (Lifesize: 306). Eventually, she came out as a lesbian.
Also while in Yale as a graduate student, Bette befriended heterosexual undergrad Kelly. Bette soon became romantically obsessed with her, and when Kelly rejected her advances, as observed later by Bette's half-sister Kit, Bette grew depressed to the brink of suicide. After graduation, Bette would move on and lose touch with Kelly.
Before Bette met Tina Kennard, she dated Alice Pieszecki for six weeks. Bette and Alice once secretly had sex while they were at the opera Lakmé (during The Flower Duet).
Tina met Bette when her then-boyfriend Eric took her to the Bette Porter Gallery. Tina found Bette to be smart, tough, incredibly beautiful, warm, and gracious. Bette noticed Tina's right earring had fallen off, and Tina supposedly put it back on.
Later that night, Tina returned to the gallery to retrieve the lost earring. Bette had kept it for her. While Tina was picking it from her hand, Bette kissed her for the first time...
Bette and Tina's relationship appears to their friends as very strong. Tina confirms to their closest friends that Bette is her "first, last, and forever" love. However, from the very beginning they seem to have problems, and even as they attempt to start a family, it is revealed that they no longer make love. Although they seem to move past this problem as the series progresses, Bette's career in the California Arts Center is shown to come between them, with Bette frequently not having time to spend with Tina.
At Bette's urging, Tina gives up her own career in order to have a child, leaving Bette as the sole breadwinner. Bette has a difficult family life, with her father Melvin only barely tolerating her relationship with Tina, and flatly refusing to acknowledge Tina's baby as his grandchild. Bette is also shown to be very bossy and domineering with Tina and everyone else. Throughout the entire series, Bette has a reputation for throwing fits and tantrums in public and private when things do not go her way.
In addition, Bette at first has a difficult relationship with her older half-sister Kit, a recovering alcoholic who has often let her down. As the series progresses, however, Bette begins to support Kit's attempts to turn her life around, and their relationship is shown to improve.
Tina's miscarriage takes a toll on Bette, and when her partner decides to become involved in a charitable organization, Bette finds that their careers make it almost impossible for them to spend any time together. At the same time, she finds herself attracted to Candace Jewell, who is working as a carpenter at the CAC. Bette tries to resist this attraction at first, to the point that she attempts to have sex with a brick wall while imagining it to be Candace, but is unable to do so, and subsequently begins an affair with Candace to fulfil her desires. When Tina discovers what is going on, she flies into a rage. In the ensuing argument, Bette rapes Tina, refusing to allow Tina to control or end the relationship. Bette aggressively holds Tina down, while Tina struggles and protests, but ultimately submits. Tina eventually leaves Bette and moves out.
In the second season, Bette resumes her affair with Candace, but soon becomes desperate to make amends for her betrayal, and finds that her break-up with Tina is disrupting all other elements of her life. Her job becomes an increasing pressure, especially when Tina's new lover, Helena Peabody, is added to the Board of Directors, and her boss hires another curator who threatens Bette's elevated position. However, Tina refuses to forgive Bette, insinuating that she is only trying to mend their relationship because she is tired of having sex with Candace.
At first, Bette feels isolated from Alice (who accuses Bette of being a "sex-addict") and the others, who she feels have mainly taken Tina's side in their argument. Although Shane and Jenny are both supportive of her (mostly because of both Shane and Jenny, also both promiscuous, having cheated on their lovers as well), it takes a while for Bette to feel on good terms with Alice again. After Tina begins to see Helena, however, the group appear to rally around Bette, who is now aware that Tina is pregnant again and has a great desire to raise their child together.
Matters are further complicated when it is revealed that Bette's father Melvin is dying from advanced prostate cancer, and is refusing treatment. A distraught Bette brings him home to die, so that he will not be trapped in a hospital, but this difficult experience leads her to reach out to Tina. Tina, who by now feels trapped by her relationship with Helena, grows closer to Bette again, and although Melvin never really blesses his daughter's homosexual relationship, he does once refer to Tina as 'Tina' rather than 'Miss Kennard' before he dies. His death is a great blow to Bette, who receives news of the loss of her job at Melvin's funeral.
Though upset and furious, Bette continues to derive comfort from her improved relationship with Tina. Bette's relationship with Kit is also vastly improved in this season, with Kit being her main source of comfort at the beginning of the season. She helps Kit to take over The Planet cafe, and begins actively involving herself in Kit's life. Eventually Tina chooses Bette over Helena, and the end of the season shows Tina asking to move back in with Bette. Tina's labor is surprisingly difficult, but their daughter Angelica is eventually born, and the end of the season shows Bette as calm and happy in her new family.
Six months later, Bette and Tina are feeling the stress of raising Angelica, Bette's unemployment and Tina going back to work for Helena at her film studio. The relationship ends yet again when Tina begins to have a renewed interest in men. She seduces a divorced father, Henry Young, and Bette has her move out. Tina moves into her own place. Bette fears Tina will take Angelica away from her by starting a family with Henry. Bette becomes a Buddhist and goes on a silent retreat, but leaves it. After seeing Angelica being raised in Tina's "white, privileged, heterosexual world", she hires the same lawyer who tried to seduce Tina last season in a custody fight. Bette retaliates by seeking sole custody of Angelica on the basis that Tina is unequipped to raise a biracial child. This time, most of their friends rally behind Bette, seeing Tina as a turncloak for using her sexuality against Bette.
At Shane and Carmen's wedding, Bette begins to have second thoughts about this, but when Tina gets the lawyer's letter and begins to take action, Bette kidnaps the baby without anyone knowing and runs away.
Bette returns Angelica to Tina, who doesn't press charges. Soon after, she becomes the dean of art at a university. Her boss, Phyllis Kroll, confesses to her that she is a lesbian. Later on, Phyllis starts dating Alice, which makes Bette feel uncomfortable due to what might happen later in the relationship.
While working at the California University School of the Arts as a dean, she begins an affair with one of her graduate students, Nadia, but soon breaks off the relationship because she realizes it's inappropriate. Then, she begins a sexual relationship with Jodi Lerner, a sculptor who has begun lecturing at the university. Tina and Bette's relationship has had some rough patches, but they become closer and friendlier with each other. Tina confesses to Bette that she still loves her and that she misses her life as a lesbian; when she meets Jodi, Tina realizes how much she wants Bette back and begins to regret ending her relationship with Bette.
Tina learns of an affair between Angus (Kit's boyfriend) and Tina's nanny, Hazel, and she informs Bette. This causes major stress to their relationship, as Bette wants to keep this information from her sister and Tina disagrees. Things become even more complicated after a disastrous dinner party, thrown by Bette for Jodi, where she learns Kit—a recovering alcoholic—is drinking again to deal with Angus's infidelity. Because of Bette's reaction to her sister's drinking, Bette and Jodi get into a heated argument. As a result of the argument, Jodi realizes that Bette's controlling ways are too much for her and takes a job offer in New York City. In the season finale, Bette, with Alice and Shane's help, steals a sign from an old building in hopes of getting Jodi back, as Jodi had once told her that she believed it would make a great art piece. It was after speaking with Tina about her feelings for Jodi that made Bette decide to get the sign, which reads '17 reasons why'.
At the beginning of L Word, Season Five, Bette and Jodi's relationship seems very loving to their friends. However, it doesn't take long before the problems begin to show. When Jodi insists on bringing Bette on her yearly vacation with her close friends, Bette finds herself annoyed and upset with Jodi and her friend's activities.
Though Bette continues her relationship with Jodi, she longs for the life she shared with Tina. Bette and Tina soon begin an affair, though they both claim to be unsure if they want anything more than their sexual reconnection. So Tina begins a flirtation with Sam, a woman who works on the set of Lez Girls. Due to her own jealousy, Bette becomes angry with Jodi when Jodi decides to have a dinner party and invites Tina and Sam. When Jodi confronts Bette about their distance emotionally and sexually, Bette chickens out of telling Jodi the real reason: she is in love with Tina. During rolling blackouts, Bette and Tina are trapped in an elevator on the way to their couples therapy session. During their time in the elevator, Bette and Tina discuss their fears about their relationship and end up making love, during which Bette tells Tina she loves her. Bette also reveals to Tina she wants to tell Jodi about their reunion after the Subaru Pink Ride.
Meanwhile, Jodi sees Bette is moody and upset about something but is not sure. By this time, Jodi has resigned from California University after one of her students held a realistic-looking gun made of soapstone to his head in front of the class as a form of art. While on their Subaru Pink Ride, Jodi learns of the affair during a game of 'I Never' when Alice begins calling Bette a "giant and 'gi-normous' cheater" for having cheated on Tina and on Alice herself when they were dating. This statement leads Jodi to jokingly ask if Bette is cheating on her. When Bette doesn't respond and Tina runs away from the group, Jodi finally realizes that Bette is cheating on her and most likely never truly loved her from the start.
After the truth is revealed, Jodi returns to Bette and completely brushes off Tina. Bette takes Jodi to her house trying to talk things over and nearly loses herself in Jodi's attempt to seduce her back. They agree to clarify things in Bette's office. It is here that Bette tells Jodi that their relationship will not work because Tina is her true love. Jodi concedes and leaves without further fight. She retrieves her personal items from Bette's place and leaves Bette an early birthday present. At the end of that eventful day, Bette joins Tina and takes both Angelica and Tina back home.
With her real admiration for Jodi, Bette introduces Jodi at the public exhibition of a new Jodi Lerner piece, entitled "Core." It turns out to be Jodi's revenge against Bette for using her: a series of videos of a single Bette saying "I love you", as well as things like "Leave me alone", "Go without me", "Stop", and "Fuck me", ridiculing Bette for her apparent promiscuity and her will to use anyone she pleases to quench her thirst for sex if not with Tina. After the shocking public humiliation, Bette returns to find solace in Tina. Later, Bette and Tina go to Lez Girls wrap party where their reunion and display of affection is admired by closest friends.
Bette moves back in with Tina, and they decide to adopt a second child using a surrogate mother. In preparation, they begin to add an expensive extension to their house.
The pair finally meet their chosen surrogate Marci in Nevada, an underprivileged Caucasian woman expecting a half African-American son. Despite the fact that Marci's family rejects the notion of giving the child to a lesbian couple, Marci agrees to give Tina and Bette her child. However, this transaction is threatened when Joyce Wishnea informs the pair that Nevada law does not permit adoption to same sex couples. A solution is reached when Bette and Tina agree to board Marci during her pregnancy, but when they arrive to the Los Angeles bus station to meet her, Marci is not on the bus, having for some reason backed out on the deal.
Meanwhile, when Bette tries to force her employee and ex-lover Jodi—who embarrassed her with a personal, accusatory art exhibit—to resign, the matter is brought before Phyllis. Jodi refuses to resign and threatens legal action not only against Bette, but against the entire university should anyone fire her. Phyllis privately tries to convince Bette that Bette herself should resign instead. Phyllis informs Bette that she had already helped cover up a potential scandal involving Bette's brief fling with her graduate student assistant, and that any potential sexual harassment proceedings from Jodi would further endanger the university's reputation. Immediately afterwards, Phyllis makes a pass at Bette at a bar, claiming she was always strongly attracted to her and could pursue a relationship with her now that Bette was no longer her employee, even if it meant leaving Joyce. A disgusted Bette quickly rejects Phyllis' advances and submits her resignation from the university.
Also in this season, Bette reconnects with her heterosexual college crush Kelly Wentworth (Elizabeth Berkley), and the pair open an art gallery together. While Bette had strong feelings for Kelly in college to the point where she was on the brink of suicide when Kelly rejected her, she now seems quite capable of remaining committed to Tina despite the newly divorced Kelly's constant flirtations with her. When a drunken Kelly finally makes a pass at Bette in Bette's house, Bette soundly rejects her, but the pair remain on friendly terms. Then Kelly accidentally breaks a glass, and Bette helps her pick up the shards. An on-looking Jenny mistakes this activity for a sexual moment between the pair, and captures it on her cellphone camera. Later, an angry Jenny threatens Bette that she will expose the footage to Tina if Bette does not first confess her "umpteenth indiscretion" to Tina.
When Tina gets a job offer in New York, she and Bette decide to relocate there and start a new life. Bette is more than happy to do this, partially to escape from the claustrophobic bubble of Los Angeles lesbian intrigue and partially to escape Jenny. She confides all of this to Kit, including Jenny's misconception.
At Bette and Tina's going away party in their home, Kit threatens Jenny to back off and is in turn shown the incriminating cellphone footage. Kit next confronts Bette, believing the footage to be a valid display of infidelity. Learning about the footage, and knowing that her previous straying will only convince Tina of Bette's supposed infidelity, Bette finally approaches Jenny with a clear, furious warning to back off. This confrontation is held near a banister with an unfinished railing, and it is the last time Jenny is shown alive. Her body is discovered in the pool shortly afterward. The series ends with Bette and all her friends being interrogated by police, and the truth of Jenny's death unexplained. The season was supposed to linger on to a spin-off but was later canceled.
Several weeks after the television series ends, footage of Bette's police interrogation appears on Showtime's L Word website ("The Interrogation Tapes"). For some reason, this footage leaked onto YouTube first. Although she does not divulge any information regarding Jenny's death, Bette confesses to being secretly angry and devastated by the fact that Tina never asked her to carry their second child.