Wonderfalls

Caroline Dhavernas as Jaye Tyler – A 24-year-old graduate of Brown University, at the start of the series Jaye is discontentedly working as a sales clerk at Wonderfalls Gift Emporium and living in a trailer. She avoids her loving – and overbearing – family, whose successes she seems determined not to emulate, spending most of her time at The Barrel, a local bar at which her best friend, Mahandra, is a cocktail waitress.

Despite her being extremely caustic and a deliberate underachiever, Jaye's life takes an odd turn when various muses, in the form of animal objects, begin talking to her and delivering cryptic instructions. At first uncooperative, Jaye eventually breaks down after they inflict on her various forms of passive coercion, such as keeping her awake all night by singing, and harassing her with their messages when she is around others, forcing her to accede in order to avoid appearing crazy.

Jaye's attempts to ignore or go against the messages often result in unexpected misfortunes, such as when Jaye's father is hit by a car. Jaye's guilt over the event leads to her following the muses' instructions throughout the rest of the episode, only to discover that her father's injury was, in fact, a blessing, as it led his doctors to discover a potentially life-threatening blood clot. As the series progresses, Jaye becomes more willing to follow the muses' instructions, although she fights them when they make her do things she doesn't like, such as driving Eric back into the arms of his wife.

Through the course of the series, Jaye undergoes a subtle, yet discernible personality shift, as the good deeds she unwillingly performs begin to affect the way she perceives the world around her.

Katie Finneran as Sharon Tyler – The eldest of the Tyler siblings, Sharon is an immigration lawyer and the most ambitious member of the family. Sharon constantly finds herself having to help Jaye – particularly when she has legal trouble – even though there is a strong degree of animosity between the sisters at the start of the series. To Jaye, Sharon is everything she doesn't want to be: goal- and career-oriented, constantly seeking their parents' approval, extremely high-strung, and apparently with little enjoyment of her life. Meanwhile, Jaye's constant pranks and somewhat callous disregard for her sister have made Sharon highly resentful.

In the first episode, when Jaye discovers Sharon's "big secret" (that she is a lesbian), they admit that despite their animosity they do love each other. Jaye not only keeps Sharon's secret from everyone else, she even helps her out on occasion when someone (particularly their parents) comes close to discovering the truth. In turn, despite great shows of reluctance, Sharon always helps Jaye when she needs it, and even comforts Jaye when she is in despair over Eric.

Tyron Leitso as Eric Gotts – Jaye's love interest – is introduced in "Wax Lion" under unusual circumstances: Six days prior to the events of the pilot, Eric arrived in Niagara Falls for his honeymoon with his new wife, Heidi. Upon returning to their hotel suite one day, he discovered Heidi "servicing" a hotel bellman. Anguished, he retreated to The Barrel and sat and drank for three straight days, after which the owner offered him a bartending job.

Extremely sweet, thoughtful, and kind, Eric is the antithesis of Jaye's often-abrasive personality, although he seems intrigued by her brashness and convinced that she is not as uncaring as she claims to be. Although his interest in Jaye is reciprocated, his light flirtation is often rebuffed because of Jaye's fears that she is going crazy, his status as a married man, and Jaye's deeply rooted fear that she will hurt him. Toward the end of the series Eric's wife Heidi arrives in Niagara in an attempt to win back her husband. Despite having fallen in love with Jaye, her refusal to admit her feelings (caused by the warnings of the muses, rather than her own inclination) leads him to remarry Heidi and decide to leave Niagara.

In the final episode Jaye is held hostage by a bank robber at Wonderfalls; because of deep feelings for Jaye, Eric is able to interpret her coolness toward him as an indication that something is wrong and alerts the police. Eric's explanation of why his suspicions were aroused in an interview on the local news finally convinces Heidi that there is no hope for her marriage to Eric. At the end of the final episode, he returns from New Jersey to Niagara, having divorced Heidi. His explanation helps Jaye to understand that the muses' warnings regarding Eric were in order to allow him to come to terms with his relationship with Heidi and end things with her properly.

Lee Pace as Aaron Tyler – Jaye's brother. Aaron is a PhD student of comparative religions, and the only one of the Tyler siblings still living at home. Aaron is the most easygoing of his siblings, exhibiting a laconic attitude toward his family and toward Mahandra's tension over their burgeoning relationship (although her refusal to acknowledge it doesn't seem to deflect his interest in her, or in legitimizing their relationship). Although they constantly bicker, it is clear that Aaron and Jaye are close (Jaye even asks Sharon at one point if she is angry that Jaye and Aaron like each other better than they like her).

Aaron is the only one during the series who learns of the full extent of Jaye's communications with the muses, a result of his worry over her strange behavior. Although he first believes that she is crazy, and despite being a self-proclaimed atheist, when things that the muses tell her start coming true Aaron begins indulging his sister's claims, even to the extent of helping her try to rid herself of all the animals that have talked to her. Eventually, Aaron reluctantly suffers a sort of existential crisis when, during a session with Dr. Ron, a cow creamer that had communicated with Jaye mysteriously seems to prove that they really have been talking to his sister. When Jaye asks him to gather all of the animals, he attempts to talk to them himself, exhibiting a desire to be proven wrong about his belief that there is no higher power.

William Sadler as Darrin Tyler, a highly respected physician, and Jaye, Sharon, and Aaron's father. Darrin is a loving father to his children, meddling particularly in Jaye's life, as he worries that she isn't doing anything to reach her potential. He bails both Jaye and Yvette out of jail in the episode "Crime Dog". When Jaye apologizes for making him compromise his political beliefs, he tells her that family comes first, and even expresses gratitude toward Jaye for hitting him with her car (because it's discovered that he had a potentially fatal blood clot in his leg). Like his wife, Darrin shows constant support to Jaye, even though he is clearly worried that she is not sharing with them what is going on with her.

Diana Scarwid as Karen Tyler – the Tyler siblings' mother. Beautiful and very popular as a successful writer of bestselling travel book guides, Karen is friends with more of Jaye's high school classmates than Jaye herself was.

Karen's deep love and concern for her children often manifests as criticism and a lack of respect for their personal space – in the "Crime Dog" episode, Jaye challenges Aaron with the information that Karen goes through his things when he isn't home. It's clear that Karen is devoted to her family and particularly worried about her youngest daughter. Jaye even jokes that Karen had a tracking device installed in her at birth, thus never allowing Jaye to escape her family. Karen often questions whether Jaye's "problems" are as a result of her and Darrin's parenting, and clearly wants Jaye to open up to her. Often, Karen and Darrin's attempts to show their support result in annoying Jaye; despite that, Jaye recognizes that her mother not only loves her, but is capable of great insight and compassion – particularly toward the people she loves.

Tracie Thoms as Mahandra McGinty, Jaye's best friend since childhood. Mahandra is a cocktail waitress at The Barrel and a co-worker of Eric's. Like Jaye, she has a sarcastic, dry sense of humor, and a vengeful streak – particularly when first encountering a despised former high school classmate in the episode "Pink Flamingos" or in "Barrel Bear" perceiving Jaye's attempts to help the rival of a woman Mahandra has aligned herself with, as a mockery of Mahandra's hometown pride.

Mahandra often functions as her friend's voice of reason, even to the extent of warning Jaye away from Eric, fearing that her friend will only break his heart. Despite her often blunt manner, she and Jaye have always considered her to be "the nice one" in their friendship. Later in the series Mahandra begins a secret relationship with Jaye's brother, Aaron, which she desperately tries to conceal from Jaye and the rest of the Tyler family. The relationship is "outed" in the episode "Caged Bird" when Jaye is taken hostage at the store. Fearing for her friend's safety, Mahandra hurries to Wonderfalls, but stops short of approaching Jaye during the aftermath. When Aaron sees her, she breaks down, and Jaye and the other Tylers see them kissing.

Jewel Staite as Heidi Socket-Gotts – Eric's estranged wife. Heidi makes her first full appearance in the series in the episode "Safety Canary" when she arrives in Niagara in an attempt to win Eric back. Although she presents to Eric a repentant and loving front, she deliberately manipulates him to suit her purposes – faking amnesia and slipping him male-enhancement drugs in an attempt to get him to sleep with her. She hates Jaye, perceiving her as a threat to her relationship with Eric.

Although Eric seems to recognize Heidi's manipulations, Jaye's inability to confess how she feels for him eventually drives him back to his wife. When Heidi sees Eric on a news report explaining how he knew to alert the police to the hostage situation in "Caged Bird", she begins to realize that although Eric might forgive her, he is truly in love with Jaye. On her way to tell Eric that she is giving up him and their marriage, Heidi collides with the van in which Jaye is being held hostage. This action causes the bank robber who has taken Jaye to be hit by an ambulance, saving Jaye's life. Although in the aftermath of the hostage events it appears that Eric and Heidi have reconciled and returned to New Jersey to begin their life together, Eric reveals later that he only went to help her get settled and to close the book on their marriage by getting a divorce.

Neil Grayston as Alec "Mouthbreather" – Jaye's co-worker. A large part of Jaye's animosity toward Alec is that although he is still in high school, he is now her boss and doesn't hesitate to order her around. She also resents that he was promoted over her. Despite his attempts to be assertive over Jaye, she generally ignores him.

Chelan Simmons as Gretchen Speck-Horowitz, one of Jaye's former classmates. (She later makes an appearance on the TV series Hannibal, in which Dhavernas co-stars as a different character.)

Although the show's creators had intended for the 13 episodes of Wonderfalls to tell a standalone story, they discussed plans for second and third seasons in an interview and episode commentaries featured on the 2005 DVD release of the series. Among the projected storylines mentioned on the DVD:

• In the second season, Jaye's therapist would document their sessions, eventually publishing a book on her, which would lead to her being institutionalized with "Joan of Arc Syndrome" in the third season. Once institutionalized, she would begin to affect the lives of the other residents there.
• An accidental-pregnancy plotline was also planned for Jaye's sister Sharon. Having slept with her girlfriend Beth, who had just slept with her ex-husband, in the first season, Sharon would later find out that she was pregnant from him. This "miracle pregnancy" would solve one problem between Beth and her ex-husband: they couldn't have children.
• A new wax lion, one who was intact, would be introduced, who would advise Jaye against listening to what the original wax lion said.
• In the second season, Aaron would begin to regard his sister as a spiritual leader.
• The young boy (Spencer Breslin) who received a mail order bride from Russia in the episode "Lovesick Ass" would return in the opening of Season 3 in the same institution as Jaye, suffering from pyromania after Jaye broke his heart.