Junior Mints, Yoo-hoo, Drake’s Coffee Cakes, puffy shirts: These are all things Jerry Seinfeld has endorsed — at least in his alter ego on his classic sitcom. Now, add Microsoft software.

Mr. Seinfeld will be a key pitchman in a planned $300 million fall advertising campaign for the software giant, a person familiar with the plans confirmed to the Associated Press on condition on anonymity because the deal has not been formally announced.

The Wall Street Journal first reported the plans. Citing people close to the situation, it reported the comedian will be paid $10 million for appearing in ads with the chairman of Microsoft, Bill Gates.

It’s Microsoft’s latest move to try to capture some of the cool quotient that rival Apple has appeared to win so effortlessly.

But for younger consumers especially, can Mr. Seinfeld turn the image tide for Microsoft?

“Seinfeld does represent sort of a challenge,” the television editor for the weekly advertising magazine Ad Age, Brian Steinberg, said. “He’s not Dane Cook. He’s got a more sophisticated everyday take on things. He often comes across as a questioner of conventional wisdom but also can be kind of a crank. It’s a fine line to walk when you’re dealing with a younger person.”