From 1989 to 2005, Foster was chairman, president, and chief executive officer of Newfield Exploration Company, headquartered in Houston.

In addition to his tenures at Newfield and Tenneco, Joe Foster's corporate directorships included Baker Hughes, Inc., McDermott International, Inc., New Jersey Resources Corporation, Valero Energy, Dual Drilling, and Targa Resources, Inc. From February through August 2000, Foster served as interim chairman, president and chief executive officer of Baker Hughes Incorporated, while the company searched for a new chief executive.

In 2001–2002, Foster served as the independent trustee for a large portion of Texaco's refining and marketing assets which were required to be divested in the course of the Chevron–Texaco merger.

He served as chief executive officer until his retirement from active management in January 2000, and remained as chairman of its board until May 2005.

Foster founded Newfield in 1989 as a private start-up with $9 million of equity capital provided by himself, other employees, a group of Houston investors, and University of Texas Endowment funds.

In addition, he participated as a non-operating partner in drilling oil and gas wells in the Gulf Coast area.