The RMS-106 Hizack served as one of the three main mobile suit models that filled the Earth Federation Forces' ranks from U.C. 0084 to U.C. 0087, alongside the RMS-179 GM II and RMS-117 Galbaldy β. The Hizack was the primary mobile suit of the Titans and was used in many missions to eradicate anti-Federation dissidents. However, with the AEUG deploying more advanced mobile suits as the Gryps War progressed, the Titans began to search for a more powerful machine to replace the Hizack. Anaheim Electronics' RMS-108 Marasai was initially considered as a replacement, but a decision was eventually made for the Titans to develop their own mass-production mobile suit, leading to the RMS-154 Barzam. Despite this, the Hizack continued to operate as Titans primary mobile suit and still outnumbered the Barzam by the end of the war.
Following the Gryps War, the Earth Federation Forces sought to distance itself from the Titans by mothballing many of the mobile suits the group used, including the Hizack, replacing them with the MSA-003 Nemo and RGM-86R GM III. During the First Neo Zeon War, Neo Zeon appropriated an unknown number of Hizacks, and several of them participated in the Battle of Axis, fighting on both the sides of Haman Karn and Glemy Toto's Neo Zeon factions.