Sweeney’s resignation comes shortly after James Mattis, who Sweeney served under, left his post earlier than planned. Mattis had announced his resignation, initially planning to stay in his post until February, following President Donald Trump’s plan to pull U.S. troops from Syria. Department spokeswoman Dana White also recently left her role, the BBC reports.

“After two years in the Pentagon, I’ve decided the time is right to return to the private sector. It has been an honor to serve again alongside the men and women of the Department of Defense,” said Sweeney in a statement Saturday night posted on the Department of Defense’s website.

In 2014, Sweeney retired as U.S. Navy rear admiral and had overseen the U.S.S. Cole’s restoration according to the Department of Defense. Sweeney spent time working in various roles for the private sector before he became chief under Mattis in January 2017. Sweeney graduated from the Naval Academy in 1982. He has also served as executive assistant to the under secretary of the Navy and executive assistant to the commander of the Joint Forces Command, reported The New York Times.