Why Retired Generals Rarely Lead The Pentagon By all accounts, retired Army Gen. Lloyd Austin, President-elect Joe Biden’s pick to lead the U.S. Defense Department, is eminently qualified to be secretary of defense. A man who achieved the rank of four-star general and succeeded at every turn during his 40-year career, Austin displayed valor and courage while serving the country for nearly half a century. Please share this article - Go to very top of page, right hand side, for social media buttons. Ironically, though, Austin’s lengthy military career has created a sticking point in his confirmation process. The law requires a service member to be out of uniform for at least seven years before assuming the civilian role of secretary of defense.