Stevens will step down in January and was supposed to be replaced by Chris Kubasik who was Lockheed Martin's president and chief operating officer under Stevens.
But when it came to light in November that Kubasik had a personal relationship with a subordinate, Kubasik was asked to resigned.
Now, Lockheed Martin will have its first female CEO when Marillyn Hewson takes the top job on January 1.
Hewson has led the company's electronic systems division since January 2010. She has been with Lockheed for 29 years.
In December, Lockheed also received a Pentagon contract that guarantees the final installment of $127.7 million for the fifth production lot of F-35 fighters. Lockheed assembles the F-35 in Fort Worth.