Miller was a member of the Asset Containment Unit, an InGen security force that specialized in controlling prehistoric reptiles. Holding the rank of trooper, he worked at the Jurassic World theme park and was part of a squad led by Austin.
When the genetically-modified Indominus rex broke out of its enclosure, Miller was among the ACU personnel sent in to recapture it. Their mission turned catastrophic when the Indominus ambushed the team by first tearing out the implant they were tracking it with and then using its camouflaging abilities to launch a surprise attack, resulting in deaths of many of the guards. As the surviving personnel attempted to retreat, Miller covered them by firing at the dinosaur with his shotgun. This failed to have any effect on the Indominus, which promptly ate him in one bite. Nevertheless, his sacrifice bought the remaining ACU members enough time to escape.