Coca-Cola CEO James Quincey told CNBC on Tuesday that the beverage giant has boosted sales of Diet Coke by tapping into the millennial demographic through targeted marketing and "flavor innovation."

Quincey also touted Diet Coke's a new "sleek can," saying it presents a "more modern, more engaging package" to a generation that appeared detached from the product. Earlier this year, Coca-Cola launched the new slim Diet Coke cans along with flavors including ginger lime and feisty cherry.

"I think that combination, executed by the bottlers, has brought people in," Quincey told CNBC's Sara Eisen on "Squawk on the Street." "And they found something that they like in something that is ultimately a great tasting beverage."

Atlanta-based Coca-Cola generated double-digit growth, in part from its diet soda category, that helped lift quarterly earnings and revenue above expectations.

In response to inflation and tariffs on aluminum, Coke had to increase prices to cover rising manufacturing costs, said Quincey, who joined CNBC just hours after the company reported third-quarter results.

Those challenges encouraged the company to "bring some innovation into the packaging" and adapt to changes, he said. "I think that's what's allowed us to continue to grow volumes, even though we had to pass through some of the input cost into price because we're providing something that's interesting to the consumers."

Hoping to continue driving more growth, Quincey defended Coke's coffee strategy. He said it offers a "number of very important opportunities" to enter the global market. To compete with established names such as Starbucks and Nestle, Coca-Cola's $5.1 billion acquisition of London-based coffee chain Costa attaches the iconic American company to a brand with "international portability and supply chain," he said.

"There are a lot of immediate consumption channels," Quincey said of the coffee company. "We can work with those customers and those channels. We can go to the at-home occasion with pods and beans and capsules. And we can bring ready-to-drink coffee to many more parts of the world."

— Reuters contributed to this report.