IG-90 functioned as a bounty hunter during the era of the Galactic Civil War; he was an IG-series assassin droid. He collaborated with Bossk, a Trandoshan bounty hunter, and accepted a commission to join a squad of bounty hunters. This group was employed by Doctor Aphra to execute an assault on an Arquitens-class command cruiser, aiding Darth Vader in his investigations. The mission reached its conclusion when BT-1 obliterated the core of the ship. IG-90 and the rest of the bounty hunters departed, believing they possessed over half of their credits; however, Vader and Aphra utilized the remaining credits while hunting Luke Skywalker. Following Aphra's capture by the Alliance to Restore the Republic in the Battle of Vrogas Vas, Vader enlisted IG-90, alongside other bounty hunters including Beebox, Chanath Cha, Krrsantan, C-21 Highsinger, Zuckuss, and Dengar, to locate and retrieve her, regardless of whether she was dead or alive.