Arthur von Streit first served as security advisor and aide to Duke Otto von Braunschweig, a leading noble of the Galactic Empire. While at the Braunschweig estate during Marquis Klopstock's assassination attempt on Kaiser Friedrich IV, Streit spearheaded survivor interviews and traced the explosion's source. Amid escalating political tensions before the Imperial Civil War, he proposed assassinating Reinhard von Lohengramm to Braunschweig. Following Captain Anton Ferner's failed attempt on Reinhard's life on 6 April 797 UC, Streit surrendered to Reinhard and retired. He expressed disillusionment with Braunschweig's faction yet declined Reinhard's initial invitation to join his staff.

Streit later returned to imperial service as a senior adjutant to Reinhard von Lohengramm, continuing in this role after Reinhard ascended as kaiser of the New Galactic Empire. Reinhard deemed Streit's talents too significant to remain idle, despite objections from other admirals concerning Streit's prior allegiance to Braunschweig. Oskar von Reuenthal viewed the appointment as a political statement, demonstrating Reinhard's power to command loyalty even from former adversaries.

As Reinhard's adjutant, Vice Admiral Streit participated in pivotal events including Operation Ragnarök, the Battle of Vermillion, and the suppression of Oskar von Reuenthal's rebellion. He was also present during Baron Heinrich von Kümmel's assassination attempt, an event orchestrated by Terraist conspirators planning to detonate Seffle particles beneath a courtyard reception. During this incident, Streit witnessed Reinhard disarm Kümmel after a confrontation.

Streit remained alive as of 801 UC, retaining his position within the imperial command structure throughout these conflicts.