iPhone Duo Took Years of Work as Apple CEO John Ternus Explains Foldable Design Choices

Apple recently underwent a leadership shake-up, with John Ternus taking over from Tim Cook as the Chief Executive Officer. Shortly after taking the reins, Ternus took to the stage during the company's September event to unveil the first-ever foldable iPhone, dubbed the iPhone Duo. In a recent interview, the CEO spoke about Apple's approach to product design, the development of its first foldable iPhone, and its evolving artificial intelligence (AI) strategy.

John Ternus on iPhone Duo, Apple's AI Strategy, and More

In an interview with TIME for its Best Inventions of 2026 issue, Ternus said Apple's work on foldable devices began much earlier than the launch of the iPhone Duo. In 2011, he and five other Apple engineers reportedly filed a patent application exploring foldable electronic devices, including the batteries and circuit boards such products would require. Ternus said he believed flexible OLED displays would eventually become possible. Apple, however, still had to overcome several engineering challenges before turning the concept into a commercial product.

Reflecting on foldable smartphones from other manufacturers during the 2010s, the Apple CEO said, “The other examples in the world felt kind of cheap and crappy.”

Richard Dinh, Vice President of Product Design at Apple, told TIME that Ternus encouraged the team to keep pushing for a better solution. Dinh reportedly recalled asking whether they should use a surface material similar to those found on rival foldables, despite concerns about its shortcomings.

Ternus reportedly told him to continue until he knew the design was right, giving the team confidence to explore alternatives. The result is the iPhone Duo, which uses a custom polymer surface with a nanotexture finish, built over a hinge containing more than 100 precision components.

The Apple CEO also addressed Apple's AI strategy, including its decision to use Google's Gemini to help power the new Siri AI experience. When asked about Apple's reliance on technology developed by another company, Ternus said there was no requirement for Apple to build every component of its products itself. Instead, he said, the company focuses on areas where it can offer a differentiated experience.

Ternus argued that Siri AI's advantage comes from its access to information across a user's device, with permission. “Everything in your life is on your phone,” he told TIME. The Apple CEO added that Siri could use this context to help people find information and complete tasks in ways other assistants might not.

Ternus also spoke about the pressure of his first major iPhone launch as CEO. During the iPhone Duo's public unveiling in September, viewers noticed his hands shaking while he demonstrated the device during a livestreamed interaction with creator IShowSpeed. Ternus attributed it to a lack of sleep and the excitement of launch day, saying he was running on adrenaline, caffeine, and anticipation.