By Michael Dabaie

Lockheed Martin Corp. said Monday that James Taiclet became president and chief executive in a planned leadership transition.

He succeeds Marillyn A. Hewson, who has served as chairman, president and CEO since 2014 and president and CEO since 2013. Ms. Hewson will become executive chairman of the board and provide ongoing support for the leadership transition, the company said.

The Bethesda, Md., security and aerospace company said in March its board elected Mr. Taiclet president and CEO effective June 15.

Mr. Taiclet had served as chairman, president and CEO of American Tower Corp. since 2004 and CEO since 2003.

Write to Michael Dabaie at michael.dabaie@wsj.com