Cruella first meets Lars when she stumbles into an art house show. Lars' main style of art is shown to be black spots on a white surface, similar to that of a Dalmatian's coat. Impressed with the artwork, Cruella demands to meet the artist, to which Lars reveals she already has and the two introduce each other. Lars is attracted to how Cruella is able to see his artistic vision and agrees to do a painting for her in exchange for her being his muse.
On his first painting for her, Cruella comments that it is all wrong, despite his claim for it to be his best work yet. Cruella notes it needs to be better than his best, and after being seduced by Cruella, Lars vows to paint another canvas, one after another, until he has found artistic perfection and will not stop until Cruella is pleased.
Many failed attempts later, he submits in defeat about not being able to please Cruella, but she assures him that all he needs is some inspiration. She later returns with the captured Dalmatian puppies, Lars then bursts out with joy and delight, hugging the puppies, believing that Cruella wants him to paint a portrait of them, when in fact she wants him to make art with the puppies (use their coats as canvas, etc.).
Shocked and horrified by this, Lars refuses, commenting how he may be eccentric, but is not a sicko and says she will not harm any of the puppies if he has anything to say about it. Cruella then gags him and ties him up in one of his paintings and calls Lars a disappointment, but figures if she cannot have a portrait, at least she can get a coat.
After Patch frees his brothers and sisters from Cruella's cage crates and they make their way out out of the warehouse through a roof window, Lars is later freed by Thunderbolt and he drives him to an alley to help Patch stop Cruella, Jasper, and Horace before going to summon the police, whom he later gives a statement to, describing how mean Cruella was to him and the puppies and then he passed out.
In the credits, a newspaper of him is shown revealing him to be labeled as an artistic genius who made lots of money for all of his new spot paintings and the piece of splatter art that Patch made when being chased by Jasper and Horace earlier.
While Lars appears in the Patch's London Adventure video game, he is shown as an enemy who will attack Patch in the studio levels. This is despite the fact that, in the film, Lars refuses to let any harm come to the Dalmatian pups and also helps Patch against Cruella. He uses his paintbrush as a weapon in the game.
- Lars is sometimes thought to be German, but this is false, as he normally speaks with a French accent and has even used French terms (such as bourgeois).
- Lars rarely uses contractions in his vocabulary, giving him a rather distinctive dialogue.
- It is unknown why he was cast as an enemy in the Patch's London Adventure video game.