- “Package retrieved; need immediate evac, over. Package retrieved!”— Hartley on recovering a UNSC Laser Designator
He participated in the Battle of Sector Six during the Battle of Earth, retrieving a laser target designator to extrapolate Spartan John-117's crash-landing coordinates. Corporal Rymann gave Hartley covering fire and the two troopers evacuated in an M12 Force Application Vehicle, better known as a Warthog. Hartley rode in the passenger seat, providing suppressing fire against the surrounding Covenant loyalists deployed to Sector Six. During this escape, Hartley was hit in the abdomen by a Spiker round, a crude but effective weapon designed and produced by the Brutes . The Warthog was then re-routed to the nearest field medical officer, who was in Sector Six, attached to another Marine outfit which was under heavy enemy fire.
When the Warthog arrived at the Marines' position, corpsman, R. Coney, attended to Hartley's wound, removed the Spiker round from his abdomen, and applied biofoam to ease the pain and allow Hartley to continue combat until he could be properly treated for his wound. During this time, Rymann was nearly killed by a Brute Chieftain with a Gravity Hammer, when the Chieftain unexpextantly came up behind him and slammed his hammer over Rymann's body.
With John-117's landing only minutes away, Hartley was able to acquire the Laser designator, and secure the exact coordinates of the Spartan's re-entry path using the scanner, then pass along the information to the rescue team standing by. Once the SPARTAN's position had been fixed, the order to fall back was given; Hartley was able to retreat and was last seen sitting inside the entrance to a UNSC bunker as the doors closed behind Corpsman Coney and Private Scottlee.
Despite his wounds, he was capable of aiming the Laser designator and then making his way inside the bunker without any support; it is thus likely that he later returned to action.
- Hartley's helmet visor is tinted orange, unlike most ODSTs. This is reminiscent of the MJOLNIR ODST helmet.