Greg Christie, the designer who helped spearhead the creation of the interface for Apple’s iPhone, is leaving the company after two decades.
Apple confirmed Wednesday that Christie would retire later this year after playing a pivotal role in the development of the iPhone.
“He has made vital contributions to Apple products across the board, and built a world-class Human Interface team which has worked closely with [Senior Vice President] Jony [Ive] for many years,” said Apple spokesman Steve Dowling.
Apple site 9to5Mac reported earlier Wednesday that Christie was leaving amid a dispute with Ive.
Christie was responsible for the slide-to-unlock feature that is one of the patents at dispute in the ongoing Apple-Samsung trial. He testified last week about its development, noting it evolved as a companion to the first iPhone’s touchscreen as a way to avert unintentional dialing.
While some Apple developers knew Christie from his appearances at the company’s Worldwide Developer Conference, he was not a widely known public persona prior to his appearance in the trial. He had never spoken publicly about the birth of the iPhone until Apple made him available for interviews with the Wall Street Journal and National Public Radio.
During his testimony, Christie told the story of how he came to Apple after reading an article about the Newton handheld computer and becoming enamored with the device. Christie testified he spent his last $700 to buy one and borrowed another $700 to get the developer kit needed to write software for the portable computer.
“It just really excited me about what the future of computing could be,” Christie said.
Christie is self-taught when it comes to technology; he didn’t own a computer until he was a sophomore in college and put one together from parts.
In the mid-1990s he started working at Apple, first as a contractor testing Newton software and later as a full-time employee testing and then writing software and fixing bugs.
Christie was managing the Mac OS X user interface team when Scott Forstall approached him in late 2004 about working on a phone, later code-named Purple, that became the iPhone.
By the next year, Christie testified, CEO Steve Jobs was frustrated with the progress the teams were making and threatened to reassign the project. After a marathon two-week session, Christie and the team pulled together various features in development and managed to sway Jobs with their approach.
“He was very excited,” Christie said. “This was clearly what he had been looking for and what he had been asking for.”
Christie and his team leave a legacy of software design features that millions of iPhone users take for granted, but which were revolutionary at the time of the iPhone’s introduction in 2007. These innovations — stitched, as Christie told NPR, from “idea fragments” — include the ability to make calls with the touch of a number found in an address book or to text a friend and have the conversation displayed in a unified fashion on the screen (instead of listed chronologically).
This article originally appeared on Recode.net.