Mr. Cartwright meets Daria when she goes to see him regarding Ultra-Cola's advertising at Lawndale High. She is unable to convince him of the validity of her position right off the top - in fact, he suggests that her entire purpose in arguing the point is to provide herself with an extracurricular activity to put on her college applications. Daria is able to convince him otherwise, but he still doesn't accept the validity of her position right away.

When Mr. Cartwright actually visits Lawndale high and sees that Ms. Li has gone insane and that the students are running through the halls gulping down soda at her insistence, he takes action to alter the contract with Ultra-Cola so that it's more limited.

Mr. Cartwright attends the Lawndale High graduation ceremony.