AT&T Vice Chairman Ralph de la Vega, who played a critical role in bringing the iPhone to the U.S. market, will retire on Dec. 31, a spokesman for the wireless carrier said on Thursday.
De la Vega, 65, who is CEO of AT&T's Business Solutions and International unit, will be succeeded by Thaddeus Arroyo, who heads AT&T's Mexico operations, AT&T spokesman Fletcher Cook said.
Kelly King, who was previously the president of the consumer mobile division in 12 U.S. states, will replace Arroyo as chief executive of its Mexico business, according to a company statement.
AT&T bought Mexico wireless carriers Iusacell and Nextel Mexico last year to expand its footprint in Latin America. It has been integrating the two companies' networks to face off against Carlos Slim's America Movil, the dominant carrier in that region.
Get Data Sheet, Fortune’s technology newsletter.
De la Vega will leave after a 42-year run at AT&T, where he led the company's launch of the first iPhone from Apple (aapl) through an exclusive partnership. He has also held other executive roles in the telecom industry, including that of chief operating officer of Cingular Wireless and president of BellSouth Latin America.
In January last year, AT&T (t) picked Arroyo to lead the network and business expansion of its Mexico operations. He has previously held roles such as president of technology development and chief information officer at AT&T.