Office Display Acting Defense Secretary Richard V. Spencer's biography is displayed by his office at the Pentagon, July 15, 2019. Spencer became acting secretary following the announcement of the nomination of Army Secretary Dr. Mark T. Esper to be defense secretary. Esper had been serving as acting defense secretary since June 24, 2019. Federal regulations require Esper to step down from that position during the review process. SHARE IMAGE: Download Image: Full Size (1.04 MB) Tags: DOD Photo By: Army Sgt. Amber I. Smith, DOD VIRIN: 190715-D-SV709-0027C.JPG Photo Gallery