President Donald Trump's pick for new Defense Secretary is an Army veteran who served in the first Iraq war and also has experience as a national security adviser on Capitol Hill as well as a defense industry lobbyist.
Trump on Tuesday said Mark Esper, his current Army secretary, would lead the Defense Department on an acting basis.
"I know Mark, and have no doubt he will do a fantastic job!" the president tweeted.
He later told reporters that he would most likely nominate Esper for the permanent job.
"Frankly this could happen very quickly for Mark Esper," Trump said.
"He's very experienced. He's been around all of the things that we've been talking about for a very long period of time."
The move came after acting Defense Secretary Patrick Shanahan withdrew from the job before his formal nomination ever went to the Senate, citing a "painful" family situation that would hurt his children and reopen "wounds we have worked years to heal."