Billy Mack – In his late 40s, the central character, our anti-hero, is our Inspector Clouseau on the trail of his lost career; what went wrong? Was he abducted by aliens? He believes so! But, no matter what, Billy must save his dog and turn his life around.
Boo – Eastwood Ranch Foundation rescued Twinkie from a fight ring. Billy's loyal companion, Boo, is a real trooper and loves Billy no matter what. Landlords in Los Angeles have a strict no pit bull policy which lands Billy and Boo in Monte Carlo, his 1998 Chevrolet Monte Carlo. Boo, more than once, saves Billy from a dangerous situation. She's a true "Pitfluencer" — (Pit bulls have a huge global social media presence and millions of followers).
Joey Mangipanni – Was a huge TV star. He meets Billy in a makeup trailer and convinces Billy to dump 12-Step meetings for a new and secretive Hollywood group—The Four Leaps. They don't take baby steps; instead, they leap through life. It's a program for winners founded by Charlie Sheen.
Artie Shaw – Billy's manager back in the 90s when they were just starting their careers. Billy put Artie on the map as a manager. Today, Artie is a player in Hollywood, but he has a soft spot for Billy and offers to help him get back on his feet. Artie helps Billy see the reality of the new Hollywood, "Things have changed, so you gotta humble yourself and start at the bottom."
Madelyn Funk – Runs a very successful acting school in LA based on the success of her number one student, James Franco. Billy must go to acting school as per his manager. After his manager, Artie, consults with Mark Wahlberg, they decide that Billy should go where Franco went. She is brutal on Billy.
Victor De La Warre – In his late 40s, is an old boarding school friend of Billy's, always looking for a dollar. He left the movie business to run a very successful escort agency. Victor wants to help Billy get back on his feet, and by back on his feet, he means on his back! Victor wants to pimp Billy out, marketing him to the older, wealthy women who remember Billy's "Teen Beat" days.
Bob – Billy's 12-Step program "sponsor." Even though Billy is easily led away from the 12 Steps, he always returns to the stability that Bob and the 12-Step program offer. Bob is a realist and doesn't put up with Billy's eccentricities. When Bob catches Billy embellishing stories, he barks out, "Quit pounding sound up my ass!" Bob was a former drill instructor in the Coast Guard.
Doctor Amstel – Boo's veterinarian and saves Boo's life in Episode 4 when he performs a very complex heart transplant. He really cares about Billy and Boo.
Miss Sally Grayson – Victor and Claudia fix Billy up with an older wealthy lady, Miss Grayson, who is a fan of Billy's early years. Billy is paid to take Miss Grayson to the country club and sit beside her while she plays bridge. Coincidently, Miss Grayson is the grandmother of a veterinarian, Dr. Grayson (Alison Eastwood). Billy is told he only has to escort her, but Miss Grayson has other things in mind.
Neil – Befriended Billy at a 12-Step meeting where he meets people he can con. Billy is an easy target for Neil, who hustles him out of money. Neil is connected to the seedier side of life (gambling, steroids, etc.), and Billy gives Neil a chance to make up for hustling him, but things only get worse.
Storie Hellman – A very successful child actor and later had some success, basically playing caricatures of himself. Billy's first role was in a movie with Storie. Storie was a dick to Billy on that project, and Billy resents him to this day. Storie challenges Billy to an MMA celebrity has-been charity fight. Billy and Storie fight to the death. Literally.
Doctor Grayson– Boo's regular veterinarian who refers Billy and Boo to her mentor, Dr. Amstel (Robert Wagner), for the heart transplant. Dr. Grayson is also the granddaughter of Billy's first paid date, Miss Sally Grayson (Sally Kirkland). Dr. Grayson takes a real liking to Billy and Boo and does her best to help Billy with all his vet bills.
Katrina – Billy's niece. In the 90s, Katrina visited Billy from Little Rock, stayed at his beach house in Malibu, and vowed to do anything to become famous. Today, she feels sorry for Uncle Billy and invites him to stay in the tool shed in her backyard. Eventually, she realizes that Billy is too much to handle, and she tosses Billy and Boo out on the street.
Patty – The real estate agent that Katrina hires to sell her house. Patty is also tasked with evicting Billy from the property.
Sofia – Russian ballerina who is dating a much older Russian oligarch, who agrees to finance a movie so she can win an Academy Award. Billy gets cast opposite Sofia in the film. Sofia is very sexual and tries to coax Billy into an amorous relationship.
Claudia – A beautiful Puerto Rican transgender woman. She is Victor De La Warre's right-hand man (woman). Claudia takes a liking to Billy and ultimately becomes Billy's greatest pal and maybe more.
Lisa Damage – Billy's girlfriend from the 90s. Neither one has really moved on. Billy keeps coming back to her for help and guidance. Lisa does her best to get Billy back up on his feet and, in fact, would start dating Billy again—publicly—if he was a star again.
Terrible Tony Fendericco – A mob boss in LA. Neil knows Tony through a guy, Terry, to whom he sells steroids. Terry sets up a meeting for Neil to pitch his idea of throwing the celebrity has-been MMA fight between Billy Mack and Storie Hellman. Tony places big bets on the fixed fight. When Tony gets screwed, he kidnaps Boo.
Taffy Hensel – Artie's writing and directing client, puts Billy into the lead role of his feature film, which is a combo Helen Keller/Anne Frank movie. Taffy is convinced that this movie will be a contender at the Oscars, sort of like My Left Foot meets Schindler's List in braille.
Ashtar – The leader of Billy's Alien Abductee Anonymous group. He is very wise and has an other-worldly ability to read people and predict the future. The few times Ashtar gives Billy a premonition, a warning, Billy ignores it and suffers dearly.
Lillith – A waitress at a café that Billy and Artie frequent, who takes an interest in Billy and his obsession with UFOs. She's kind of weird, like Billy. They start dating, and she introduces Billy to the world of Wicca. It doesn't end well.