When Congress authorized the creation of two new NCO pay grades in 1958, it of course left the task of naming the two new enlisted ranks up to the each of the branches of the military. The Air Force Chief of Staff polled the major commands for recommendations for the new E-8 and E-9 grades and selected the two most popular suggestions: Senior Master Sergeant and Chief Master Sergeant, respectively. The designations not only clearly reflected the hierarchy of the new NCO system, but also gave E-7 NCOs not selected for these new (and at the time fairly undefined) roles the honor of retaining the Master Sergeant titles they had worked so hard to achieve.
The original Senior Master Sergeant rank insignia featured a single upward-pointing chevron placed at the top of the Master Sergeant insignia to indicate it was one grade above that venerable rank. In 1992, the Air Force revamped its insignia designs for the top three Sergeant Ranks, moving a stripe (“rocker”) from the bottom and replacing it with another upward-pointing chevron at the top. With this move, all of the Air Force's Senior Noncommissioned Officer (SNCO) insignias featured upward-pointing chevrons, distinguishing them at a glance from the standard NCO ranks of E-5 and E-6.
More E-8 Senior Master Sergeant Insignia and DevicesThe Senior Master Sergeant metal rank insignia is authorized for wear primarily with outer garments. It’s worn on the epaulets of the Blue and White Cardigans (the latter is only worn with Maternity Jumper and Long- and Short-Sleeved Maternity blouses) and the Blue Pullover sweater. It’s also mandated for wear on the collars of the All-Weather Coat and Topcoat, as well as on the shirt worn with Medical scrubs.