- "Robt McLees is definitely the go-to guy for the gun stuff. I wanted to come up with an animation for the sniper scope, an 'idle cycle'. If you activate the scope, and then sit too long without doing anything, the animation would kick in periodically, just to keep things interesting... Simple, right?... He replied, "No way. If you adjust your scope in the field, you're dead. Snipers don't do that". That's how detailed his weapon designs are - not just guns, but how they work, and how a sniper would fire them. Amazing."
- — William O'Brien, commenting on McLees' weapon designs
McLees joined Bungie in 1995, initially working as a concept artist and weapons designer for the Halo titles. He created most of the weapons in Halo: Combat Evolved from concept to their finalised version. The Flood was designed by him, with Vic DeLeon assisting with the finishing touches. During the development of Halo 3, he switched away from art and became a writer, focusing mainly on Halo canon. McLees also wrote the short story Palace Hotel in Halo: Evolutions.
- He met Lorraine while attending American Academy of Art in Chicago, IL.
- In Halo: The Fall of Reach, there was a person known as Dr. Robert McLees mentioned by Cortana who designed the structural system created for UNSC Pillar of Autumn and who also was the co-founder of the Reyes-McLees Shipyards over Mars in 2510. This is an obvious reference to the real Robert McLees and his wife, Lorraine (née Reyes).
- "About the Authors" in Halo: Evolutions states: "If you give Robt a bite of your pizza, he'll ask for a beer. And when you get back from grabbing a beer from the fridge, like half the damned pizza is gone! WTF, Rob?!?"
- McLees is colorblind. While many of the color choices were changed by other artists between his concept art and final released games, one such color choice persists in final games: the red markings on top of the M41 SPNKR.