Carl works for Howard Blandy, and becomes manager of the Krusty Krab in the episode "Selling Out".
After the Krusty Krab was bought out by Mr. Blandy and rechristened the "Krabby O'Monday's", Carl became its manager and supplied SpongeBob and Squidward with their new outfits and employee manuals, as they too became employees of Mr. Blandy as part of the deal with Mr. Krabs. With the new ownership of the restaurant, he put a giant flat screen TV, an automated cash register, and a Krabby Patty machine in Krabby O'Monday's. Carl seems to always be cheerful and smiling, but is actually quite sinister if the employees prove inefficient at their tasks; he hires a big, strong, unnamed fish to "talk" to any employees who aren't as cheerful as he is. He also seemed to abuse his two employees, giving them loads of manuals to study that night before work the next day. He also disposes of the original Krabby Patty recipe and creates synthetic patties, made from a raw, inedible, gray substance cooked, painted, and flavored to taste like real food. Also, if seen at certain angles, he appears to be cross-eyed.
He later hires Mr. Krabs as a busboy, but pushes him over the edge when Mr. Krabs discovers how Carl is running the place. Mr. Krabs retaliates by showing the customers what their patties are really made of, scaring them off. He then sabotages the synthetic patty maker by jamming an automated cash register into the machine. Panicked, Carl asks for Mr. Blandy's help, as Mr. Krabs is a "free thinker". Mr. Blandy arrives just in time to witness the synthetic patty maker explode, creating a flood that destroys Krabby O'Monday's and sends everyone out of the restaurant. As Carl is washed away by the overflow of gray gunk, he asks Blandy, "Does this mean I won't get that raise, sir?" Carl may later have been fired by Mr. Blandy or simply found a new position elsewhere.
He makes a cameo appearance in the episode "Mall Girl Pearl."