Lockheed Martin's Hewson to step down as CEO
Lockheed Martin CEO Marillyn Hewson speaks prior to the arrival of President Donald Trump during a visit to Derco Aerospace Inc., a Lockheed Martin subsidiary, in Milwaukee, Wisconsin, July 12, 2019.

WASHINGTON — Lockheed Martin said on Monday company veteran Marillyn Hewson will step down as chief executive officer, and tapped board member and American Tower Corp boss James Taiclet as her replacement.

Hewson joined the defense titan more than 35 years ago as an industrial engineer. She held more than 20 different leadership positions within the company before ascending to the top spot in January 2013.

"I know it is the right time to transition the leadership of Lockheed Martin. I'm pleased the board agreed with my recommendation. As Lockheed Martin's next CEO, Jim will lead the company forward in its next phase of growth and value creation," Hewson said in a statement.

Under Hewson, the first woman to run America's biggest defense contractor, Lockheed Martin has seen its stock surge more than 224% through Monday's session and its market capitalization expand to $83.6 billion from around $30 billion.

In addition to pleasing the company's shareholders, the Kansas native has had to navigate testy waters with America's commander-in-chief.