"This decision is one I make with a heavy heart, as I can not think of a better group of people to serve and work with," said Gorman. "I am really going to miss working with these great troops, our veterans and their families."
Gorman was appointed adjutant general by Gov. Michael Rounds in 2003.
Rounds said that steps will be put in place to select the next adjutant general and secretary.
"It will take a very special individual to fill his shoes," said Rounds.