He was extremely thin (cadaverous) with a bent-forward head and stooped shoulders. He had the manner of an undertaker.
During the Guild Wars, he served Overseer Brucker at Kel-Morian Internment Camp-36, often doing menial tasks. Late in 2488, he brought a recently-returned Hellhound pilot to see Brucker... or so he thought. It was actually Confederate marine Jim Raynor in disguise. Brucker saw through it and ordered Raynor to be tortured.
The Confederate Special Tactics and Missions Platoon soon arrived to rescue the prisoners. Raynor was rescued during the mission. The Kel-Morians were losing, so Lumley and Brucker headed to the factory to escape in a saber command car. Lumley was driving when Raynor and company arrived. Raynor shot Lumley in the head, killing him and stopping the car.