Montross served as an assistant to General Luke Skywalker while stationed on Aquilae. Within a war room setting, Montross alerted all personnel to a massive asteroid or moon – a prototype of the Death Star – that was approaching Aquilae.
The character Montross Holdaack is featured in the second screenplay draft of The Star Wars, dated January 28, 1975. In this version, Montross is the science officer aboard a vessel commanded by Jabba the Hutt and Oxus, and he is also a friend of Han Solo. Solo seizes control of the ship by simulating a reactor malfunction, causing everyone to evacuate, and he retains Montross and Chewbacca as part of his crew; they later assist in transporting Luke Starkiller and his two droids, ultimately rescuing him during the film's climax. In this draft, Montross is almost entirely robotic, with only his head and right arm remaining organic; his surname was derived from a slight alteration of the name of an Imperial officer from the initial rough draft, Crispin Hoedaack. By the third draft, dated August 1975, Solo possesses his own ship, although Jabba still provides the funding. He once again stages a reactor issue, leading to everyone's departure, except for Montross, but Solo overpowers him and forces him to leave as well. The fourth draft, dated January 1, 1976, introduces more significant changes. Montross is now an Imperial bureaucrat, taking the place of Jabba, and informs Solo that the Mos Eisley spaceport is under Imperial lockdown; Solo must outsmart him in order to take off.