R.K. Maroon, owner of Maroon Cartoons, is first seen with an editor watching a piece of film playing through a moviola and waving his hand at his secretary as the Toon-hating private cop Eddie Valiant enters his office. When the editor wheels the machine away, Maroon turns to Eddie and asks him that how much he knows about show business. Eddie states that only there's no business like it he knows, and Maroon agrees, and says that there's no business more expensive. He also says that he's 25-grand-over-budget on the latest Baby Herman cartoon and tells Eddie he saw Roger Rabbit blowing his lines, and Roger can't keep his mind on his work, then asks him to know why. Eddie tells him because too many refrigerators dropped on his head. However, Maroon says that Roger is a Toon and advises Eddie that he can drop anything he want on his head, so he'll shake it off, but break his heart and go to pieces just like him and Maroon. Then, Maroon hands Eddie a newspaper, so he needs to read about what happened. Eddie reads aloud, "Seen cooing over Calamari with not-so-new sugar-daddy was Jessica Rabbit, wife of Maroon Cartoon star Roger."
Then, he asks what that must do with him and hands the paper back to Maroon. Maroon says that Eddie's the private detective, and he figures it out, but Eddie claims that he doesn't have time for that. Maroon declares that Jessica's poison, but her husband thinks she's Betty Crocker, and Maroon wants him to be on her tail to get him a couple of pictures, so he can wise Roger up with. However, Eddie disagrees because he doesn't work Toontown. Maroon asks what's wrong with Toontown, then says every single person loves Toontown. Eddie advises Maroon to get one of them to do the job because he isn't going. Then, Maroon tells Eddie that nobody said he had to hit Toontown, anyway, and forces him into a seat, then explains to him that Jessica sings at a joint called the Ink and Paint Club which means Toon review for strictly humans only. So, Maroon asks Eddie what he thinks, but Eddie is more interested in the drink cabinet. However, Maroon impatiently says, "Well?" Eddie, getting up to make himself a drink, says that the job's gonna cost Maroon $100, plus expenses, but Maroon claims that's ridiculous, and Eddie claims the job is, too! And Maroon agrees that Eddie's got $100 and allows him to have a drink, and Eddie does so. When he looks out of the window, some workmen drop some large wooden boxes releasing some Toon instruments which begin to play, but as he watches, a pair of eyes suddenly appear at the window which lets him out a scream.
Maroon asks Eddie that he's kind of jumpy and says it's just Dumbo. While Eddie gets up from beneath the drink cabinet and takes $100 paycheck off of Maroon, the studio keeper says Walt Disney loaned him both him and half the Fantasia stars who work for peanuts which is the best part. So, he opens the window blinds and throws a handful of peanuts out of the window, so Dumbo flies off sucking them up with his trunk. However, Eddie says that he doesn't work for peanuts and demands where the other 50 is. Maroon states that he and Eddie will call the other 50 per carrot to finish the job, and Eddie says Maroon's been hanging around rabbits too long.
That night, Maroon is later seen in his office while a tearful Roger having a whiny temper tantrum and getting very upset over Jessica playing pattycake with a Toontown owner Marvin Acme by rattling the blinds and headbutting Maroon's desk and asks them that's true. Maroon hands Roger a handkerchief, advises him to take comfort, and tells him that he's not the first man whose wife played pattycake on him. After Roger blows his nose into with gusto, he hands it back, dripping with Toon water, but Maroon hands it to Valiant who drops it into the bin with a splash, and then Roger complains that he doesn't believe it. However, Eddie tells him to believe it and took the pictures of both Jessica and Acme playing pattycake himself, and Roger flicks through the pictures faster and faster so it looks like they are moving, then throws them into the air, and then Eddie taunts Roger that he better start drinking it black because Acme's taking the cream now, and Maroon says that it's hard to believe and explains to him that Marvin Acme's been his friend and neighbor for 30 years. Then, he asks him who would have thought he was a sugar daddy, and Roger tells him somebody must have made her do it.
Maroon then hands Roger a glass of liquor and tells him to drink it, so it'll make him feel better, but when Roger does so, he turns a variety of different colors and his eyes bulge, then suddenly shoots into the air and emits a whistling sound so high-pitched that it breaks all the glasses in the room, including the one held by Eddie and the glass awards on the shelves, and as the whistling dies down just before falling his face down on the table, Roger collapses back into the seat and mutters, "Thanks, I needed that." While Eddie is shaking the liquor of his hands, he tells Maroon he thinks his work is finished, then asks, "How about that carrot you owe me, huh?" Maroon hands Eddie the check and declares that a deal is a deal, and Eddie thanks him. Maroon tells Roger he knows all it seems pretty painful now, but he advises him to find someome new. Eddie agrees and says that the dames'll be breaking Roger's door down. However, Roger suddenly comes to life again, grabs Eddie by the collar, forces him back onto Maroon's desk, and scolds him that Jessica's the only one to him, and shouts that they'll rise above this pickling peccadillo and be happy again, then crashes through the window leaving a rabbit shaped hole in the glass and the blinds. As Eddie and Maroon stare dumbfounded out of it, the blinds crash down, and Eddie tells Maroon at least Roger took it well.
He is last seen waiting in his office and putting his pistol away in his pocket very nervously just before Eddie sneaks up behind him, taps him on the shoulder, and recites the Bugs Bunny catch phrase, "What's up, Doc?" Maroon demands him that he is trying to give him a heart attack, and Eddie goads Maroon that he needs a heart before he can have an attack. He then asks Eddie that he's got the will. Eddie nods, lies to him by briefly showing him a bit of paper which is Jessica's love letter from Roger and asks the grumpy cartoonist that he has the way because he can tell him now it won't come cheap. Maroon says to Eddie he's got a lot of brass coming up to his studio by himself. While Jessica hears them talking outside right after she sticks her husband in the trunk of her car, Maroon asks Eddie how much, but Eddie tells him to give Jessica a chance to think and says Maroon takes $3,000,000 and a half. Maroon, now drawing out his pistol, scolds him that he wants to see Acme's will, but the private detective already told him that.
However, Maroon angrily grabs it from inside Eddie's jacket and reads Jessica's love letter, then asks it is supposed to be a joke and stuffs it in Eddie's belt. Then, throwing his anger right back at him, Eddie grabs a soda seltzer bottle and sprays a jet of soda in the studio keeper's eyes, knocks him in the face sending him falling flat on his back, holding him at gunpoint, and grabs him by the necktie to his feet. Maroon asks Eddie what he'll do to him, and Eddie says he'll listen to Maroon spin the Cloverleaf scenario and his story of greed, sex, and murder, and edit out the parts that he dislikes, but Maroon tells him that he's got it all wrong because he's a cartoon maker, not a murderer. Eddie says everybody's got to have a hobby and toughly puts Maroon's necktie in his editing machine and turns it on pulling his face closer. Maroon is now convinced that he tells Eddie the truth about having a chance to sell his studio, but Cloverleaf wouldn't buy his property unless Acme sold them his and says a stubborn bastard like the Toontown keeper wouldn't sell, so he would blackmail Acme with pictures of both him and Jessica, that's all there is to it.
He also explains that he's been around Toons all his life, so he didn't want to see them destroyed. Eddie asks him why, and Maroon claims if he tells him, he's a dead man. However, Eddie tells Maroon that he's a dead man if he doesn't tell him. On his last words just before his sudden death, Maroon keeps on protesting, "Unless Acme's will shows by midnight tonight, Toontown's going to be land for the freew...." At that moment, Eddie sees the reflection of a gold gun in a picture of a possum hanging by his tail in the wall. It fires 3 shots, and Maroon cries out. Eddie dives for cover behind the sofa, and the bullets slam into it, and when the gunfire stops, Eddie looks at Maroon to see him dead with 3 bullet holes in his back just before Eddie leaves the building to follow Jessica to Toontown.
Later, in Toontown, showing him the gun on the ground, Eddie made a serious discovery from Jessica that it was the dastardly Judge Doom who destroyed Maroon right after he did away with both Eddie's brother Teddy with a large piano on his head and Acme with a large safe on his head.
In comics set after the events of the film, it was shown that R.K. had a twin brother named C.B. Maroon, who was given ownership of Maroon Cartoons after his brother's death, parodying the fact that Walt Disney's brother Roy O. Disney took over the Walt Disney Studios after his brother's death.
- Maroon apparently has connections to other studios, seeing as he has been able to get several cartoon characters on loan from other studios.