Aldinger, 56, is Chairman and CEO of Household International, a subsidiary of HSBC Holdings plc, one of the world's largest financial services companies.
Aldinger joined Household as president and chief executive officer in 1994. He graduated from The Baruch School of City College of New York in 1969, and the Brooklyn Law School, where he received his law degree in 1975. He is a member of the New York Bar.
Aldinger serves on the boards of directors of Mastercard International, Illinois Tool Works, Inc., the combined board of directors of Children's Memorial Medical Center/Children's Memorial Hospital and the Children's Memorial Foundation. Aldinger is a member of the board of directors of Evanston Northwestern Healthcare. In addition, he serves on the board of trustees of the Baruch College Fund and Chicago's Museum of Science and Industry.
"Bill brings a wealth of business experience and insight to the AT&T board, and we're pleased that he's joining us at this time," said AT&T Chairman and CEO David W. Dorman.
Hostetter decided to resign for personal reasons, AT&T said. "I'd like to thank Amos for his contributions to the board since joining it in 1999. His insight and expertise were invaluable in guiding us though a major restructuring of the company," Dorman said.
With the addition of Aldinger and the departure of Hostetter, the AT&T board remains at nine members.