After a 42-year career in various incarnations of AT&T Mexico, the company’s Vice Chairman, Ralph de la Vega, will be retiring before the end of 2016. Thaddeus Arroyo, CEO of AT&T Mexico, will replace him.

De la Vega, 65, was born in Cuba and emigrated to the U.S. in 1962 when he was 10 years old. He started his career in 1974 with BellSouth (then Southern Bell) as a management assistant, eventually serving as the chief operating officer of Cingular Wireless in 2004.

In 2007, De la Vega played a key role in the acquisition of Cingular by SBC (which later became AT&T), and he was named CEO of AT&T Mobility — a role he kept until 2014, when he was promoted to President and CEO of AT&T’s combined Mobile & Business Solutions group.

De la Vega’s claim to fame was when he played a key role in bringing the iPhone to market, working closely with Steve Jobs to make it an exclusive device for the firm for years. He was also one of the first people to ever see it, and kept the secret close to the chest, even guarding it from his co-workers and wife.

“[The iPhone] dramatically changed how users interfaced with the device,” de la Vega said in an interview earlier this year. “It really highlights how it changes the expectations of people.”

As the head of AT&T Mobility, De la Vega was a vital component in taking the company from 3G wireless technology to 4G. He also coauthored the book Obstacles Welcome: How to Turn Adversity to Advantage in Business and Life, with Paul Brown. The goal of the book was to provide career and life advice to youth and young professionals

In Feburary 2016, AT&T shuffled its executive ranks to move de la Vega from mobile to the business and international operations. John Stankey, who previously ran AT&T’s DirecTV, internet and U-Verse TV units, took over the mobile operations.