The Seventeenth Army, also referred to as Chrome Shield Command, served as a Sector Army within both the Republic and, subsequently, the Imperial forces. Its primary mission was the defense of the Dustig Oversector.
During the Clone Wars conflict, the 17th Sector Army was responsible for defending a key area surrounding Malastare. Furthermore, it provided support to the 18th Sector Army during various military operations.
The 17th Sector Army, along with nineteen other sector armies, was initially activated around 22 BBY. This year marked the commencement of the Clone Wars, a civil war fought between the Galactic Republic and the Separatist alliance. Throughout the war, the Seventeenth Army maintained its headquarters on the planet of Vogel 7 and held the duty of defending the Dustig Oversector oversector. Similar to other sector armies, the command structure of the Eighteenth involved a collaboration between an experienced Jedi General and a Governor-General appointed by the Republic's Supreme Chancellor. By 19 BBY, the Clone Wars' final year, the Governor-Generals evolved into a permanent class of regional governors known as the Moffs.
As the Clone Wars unfolded, Chancellor Palpatine elevated Lynch Hauser to the rank of Moff, thereby granting him control over both the Seventeenth Army and the Dustig Oversector. The 17th Sector Army provided assistance to the 18th Sector Army in numerous military engagements.
Following the Clone Wars' end, the Galactic Empire, which had newly-risen, retained the Old Republic's twenty sector commands, including the Seventeenth Army. Under the New Order established by Emperor Palpatine, Hauser was promoted to the position of Grand Moff. The Imperial Era was largely defined by a massive military expansion, leading to a vast army that significantly surpassed its Republic predecessor. Consequently, the Seventeenth Army's total infantry strength, along with that of other sector units, was increased to approximately 1,572,864 troopers, with the majority being naturally born individuals as clones became less prevalent.