Bojack Horseman

Bojack Horseman, a self-loathing alcoholic horse currently in his 50s, whose acting career peaked when he starred in a successful '90s family sitcom called Horsin' Around. Though he began as a young bright-eyed actor, he has since grown bitter, deeply depressed, and jaded towards Hollywoo and who he has become post-fame. BoJack has been shown to be caring and insightful, but his insecurities, loneliness, and desperate need for approval often result in self-destructive actions that devastate those around him. Arnett also voices Butterscotch Horseman, BoJack's physically and verbally abusive father.

Princess Carolyn, a pink Persian cat who is BoJack's agent in the first three seasons and former on-and-off girlfriend. Earnest and unflagging, Princess Carolyn was a top agent at Vigor agency through her dogged pursuit of new talent and large network of odd personal connections. Though she struggles to find a balance between work, her troubled personal life, and taking care of BoJack and her friends, she enjoys her fast-paced hectic lifestyle. She left Vigor to start a new agency with her then-boyfriend and coworker Rutabaga Rabitowitz. After recognizing his lack of trustworthiness and confronting her fear of being alone, she ultimately decides to leave him and run the new company named VIM by herself. After several setbacks, Princess Carolyn closes VIM in Season 3, only to reopen it as a management agency.

Todd Chavez, an unemployed but well-meaning and friendly 24-year-old human slacker who ended up at BoJack's house for a party five years before the beginning of the series and never left. Although BoJack constantly voices disdain for him, he secretly cares about Todd, continuing to financially support him and sabotage his attempts to gain independence. Todd has been shown to possess a plethora of skills including an understanding of Japanese, entrepreneurial know-how, having allied with Mr. Peanutbutter for various business ideas, and writing and composing his own rock opera - Newtopia Rising, Book I: The Search for a New Utopia. His rock opera was eventually sabotaged by BoJack, who took advantage of his former addiction to video games. Todd puts the pieces together of what BoJack did string map style and begins to question his friendship with Bojack. Todd also has an uncanny knack for getting himself in absurd and extremely dangerous situations when his friends aren't around, such as getting into gun fights on several occasions, ending up in prison, and in one case switching places Prince and the Pauper-style with a Cordovian dictator. Todd's friendship with Mr. Peanutbutter landed him various jobs creating seemingly useless products. He sees the best in BoJack, despite his multitude of problems. He's usually happy, even when being insulted by BoJack. He is also almost never seen without wearing his signature yellow beanie. In the 2000s he was an aimless skateboarder, and the object of affection of his schoolmate, Emily. It is revealed in the season 3 finale "That Went Well" that he is asexual.

Mr. Peanutbutter, an energetic and cheerful yellow Labrador Retreiver who is BoJack's former sitcom rival and Diane's boyfriend (and later husband). Mr. Peanutbutter was the star of Mr. Peanutbutter's House, which, according to BoJack, "borrowed the premise" from Horsin' Around. He had a stint at filming a celebrity reality show called Peanutbutter and Jelly. Despite their rivalry, Mr. Peanutbutter cares a great deal about BoJack's opinion and admires him for his work on Horsin' Around. He has an especially good relationship with Todd, and his positive attitude and financial resources combined with Todd's outlandish schemes and plans often result in the two starting questionable business ventures, such as a Halloween store that is exclusively open in January. In the episode "Let's Find Out", Mr. Peanutbutter starts hosting his own televised game show after his film company enters bankruptcy due to his and Todd's extensive expenditures on useless products. In "Hank After Dark", it is revealed that Mr. Peanutbutter was formerly married to a woman named Katrina who was emotionally abusive. His second wife was famous actress Jessica Beil, who is portrayed as being obsessed with her celebrity status and people recognizing her. He grew up in the Labrador Peninsula, which is depicted as being populated entirely by Labrador Retrievers. "Mr." is his actual first name. He is a graduate of Northwestern University.

Diane Nguyen, a human ghostwriter, a nice, well-reasoned, misunderstood intellectual, and a Vietnamese-Americanthird-wave feminist from Boston who lives with her rich and famous boyfriend (and later husband), former sitcom star Mr. Peanutbutter. She's intelligent and sympathetic. While writing BoJack's memoir, Diane and BoJack initially develop a strong friendship that becomes increasingly awkward and strained after BoJack develops romantic feelings for her. Diane travels to the war-torn Republic of Cordovia to make a difference, but discovers that this life is not for her. Ashamed of returning to her husband, she develops a severe bout of depression, during which she drinks heavily and sleeps disheveled on BoJack's patio furniture. She is able to reconcile her feelings with Mr. Peanutbutter and gets a job at VIM ghostwriting tweets for celebrities. She is subsequently fired from VIM, and is hired to write for a feminist blog.