In 1945 the Navy began converting 24 out of the 98 "Gearing"s to radar picket ships (designated DDR in 1949) that could provide early warning of massed attack without overwhelming their Combat Information Centers. "Leary" was overhauled to upgrade her to a radar picket destroyer, which included installing the most advanced radar systems at the time. She then departed for Boston, Massachusetts where some fire control work was done. This work was interrupted by V-J Day celebrations. Later, the ship steamed to Casco Bay, Maine where she operated with a task force to assigned to develop defenses against kamikaze attacks.