Kieran Shanahan will step down from his position July 31.
Shanahan was tapped by Gov. Pat McCrory last December to head up the then-newly formed department which oversees 25,000 employees with a yearly salary of $135,000.
McCrory accepted Shanahan's resignation Thursday, according to a statement released from the governor.
Despite Shanahan's abrupt resignation, McCrory denies any speculation surrounding his departure and says it was never discussed before Thursday when Shanahan hand-delivered his resignation to the governor after less than seven months on the job.
Shanahan recently came under scrutiny for continuing to give legal advice to clients at the Shanahan Law Group after joining McCrory's cabinet.
In his resignation letter, Shanahan said he wanted to concentrate on his law firm in downtown Raleigh, other business obligations, and to support his wife, Tina, in her new role as an admiral in the U.S. Navy.
McCrory said he knew when he appointed Shanahan that he had a lot on his plate already.
"His focus wasn't going to be able to stay on this job like it needed to be, and we both agreed that would be the best move for the future," said McCrory. "Actually, when I appointed him as secretary, we knew it was going to be a tough, tough road to deal with and after six month. We felt this would be a good time after the legislative session is out. I consider Kieran a friend. I think we were lucky to have him, and I wish him the best, especially he and his wife."
In a statement released by Shanahan he said, "I've been honored to serve the governor and this great state and to have been a part of a great cabinet team. I am leaving the department stronger than when I took over in January."
In the meantime, DPS, which oversees areas like state prisons, juvenile justice, and the State Highway Patrol, will be managed by the executive team of Deputy Secretaries until a new secretary is named.