He appears in the level Stasis Interrupted on a audio log were he describes his studies with the Xeno Queen, Weyland asks for him to replace the C-285 nerve gas with C95 both lethal to humans and because he did't he was fired.
Reference stats table.
Appearances in the following;
Aliens: Colonial Marines
Dr Miller arrived as the Weyland-Yutani Facility on LV426 during construction along with other W-Y Geneticist studying the Aliens.
The events of the game are set between those of the films Aliens and Alien 3 but diverge from the film Aliens and over lap the film Alien 3.