National Aeronautics and Space Administration officials said Robert Lightfoot, the center's deputy director, will serve as acting director until a successor is named.
King has been Marshall's director since 2003. His departure ends a 25-year career with NASA that began in 1983 at the Kennedy Space Center in Florida, where he served as director of space shuttle processing and shuttle launch director.
"David's expertise and dedication will be sorely missed, not only at Marshall, but across the entire agency," NASA Acting Administrator Chris Scolese said. "As sad as we are to see him leave, we wish him the very best in all of his future endeavors."
The Marshall Space Flight Center has more than 8,400 civil service and contract employees performing a wide scope of propulsion, scientific and space transportation activities.