Christopher Kubasik, the incoming chief executive of Lockheed Martin, resigned on Friday after he admitted to an improper relationship with a subordinate, the company said.
Kubasik, who was the defense contractor's chief operating officer, had been slated to become CEO in January, replacing Bob Stevens.
Lockheed named Marillyn Newson, 58, as CEO effective Jan. 1, 2013. Stevens was named as executive chairman and will work with Hewson on the leadership transition.
Lockheed's board asked for, and received, Kubasik's resignation after the discovery of "a close personal relationship with a subordinate employee" that violated the company's code of ethics and business conduct.
Kubasik's actions "did not affect the company's operational or financial performance," the company added.
Hewson has been with Lockheed Martin since 1983. She was named president and chief operating officer-elect in April.