The dress cap worn by Commandants and former Commandants of the Marine Corps are not unique in featuring gold bullion oak-leaf ornamentation on both the visor and the front half of the hat’s crown; a similar design, for instance, is employed for the dress caps worn by Generals (O-10) in the U.S. Army. But it nonetheless stands out from its counterparts in other military branches because of the brilliances of the gold bullion contrasted against both the black cloth visor and the white fabric of the crown.
Although regulations state explicitly that the additional band of gold oak leaf ornamentation is to be displayed only on dress caps worn by the current and past Commandants of the Marine Corps, it would seem that Marine Generals who have been appointed to the Joint Chiefs of Staff are also authorized to wear it (note that the Commandant of the Marine Corps is automatically a member of the JCS). In an image from 2006, then USMC Commandant General Michael Hagee and Marine Corps General Peter Pace, Chairman of the Joint Chiefs of Staff at the time, are both wearing this dress cap at the same event.
Marine Corps Commandants are nominated by the President and must achieve Senate confirmation before beginning their four-year term. While the assignment carries a four-star rank, the Commandant exercises no operational command over Marine Corps forces, instead guiding and overseeing all aspects of the Corps’ policies, programs, and plans. The Commandant also advises the President, the National Security Council, the Secretary of Defense, and the Secretary of the Navy on all matters involving the Corps.