Some celebrities simply cannot be pleased. Just ask Ben Lashes, a talent manager in Los Angeles. This week, he landed a major motion-picture deal for a client who nine months ago was an unknown living in Morristown, Ariz., population 227.

When he told his client that she was heading to Hollywood, she looked bored. "She hates movies," says Mr. Lashes of his client, Grumpy Cat, a cat with a mouth puckered into a frown whose viral photos have ricocheted around the Internet.

Mr. Lashes, 34 years old, is an agent for Internet cats. When an ironic photograph of a feline becomes Internet famous, Mr. Lashes contacts the pet owner and offers to help strategize ways to prolong, protect and monetize. He says he operates with this question in mind: "What would Walt Disney do if he created Mickey Mouse and it went viral on YouTube?"

Grumpy Cat, the Arizona sourpuss, is Mr. Lashes's star client. The cat is having a mini-Mickey moment.

Last September, Bryan Bundesen, 34, a cable technician from Galion, Ohio, was visiting his sister Tabatha in Arizona. He snapped a photo of her cat, a mixed breed whose real name is Tardar Sauce. (Ms. Bundesen, who works as a waitress at a Red Lobster, says her daughter thought the cat's fur was the color of tartar sauce, but misspelled it.) Mr. Bundesen posted the picture on the website Reddit. People thought it was funny. Many began to overlay the photo with sentences expressing what they imagined to be the cat's irritation with humans: "I thought I could not be more disappointed…you proved me wrong," reads one of thousands. "There are two kinds of people in this world…and I don't like them," says another.