Harold is a man of average height with long, brown hair which he keeps parted and swept out of his eyes. When not wearing the standard Scout Regiment uniform, he can be seen wearing a long-sleeve shirt with another short-sleeve shirt over it, and long, gray pants.
Harold appears to be a very kind man, spending extra Scout Regiment funds to provide meat for his comrades in celebration of their impending expedition. He also seems to be rather naive, trusting his subordinates in the regiment to be able to control themselves when presented with meat, and trusting Flegel Reeves to keep the news of the mission to reclaim Wall Maria a secret.
Harold is seen attending a meeting between Erwin Smith and the other Scout Regiment officers to discuss the recent revelations involving Eren Jaeger's father Grisha. As the meeting concludes and the officers depart, Harold suggests serving red meat to the soldiers, which the others approve.
Harold spends what little funds the Scout Regiment has remaining to buy meat from the Reeves Company for his comrades, in celebration of their impending expedition to retake Wall Maria. However, he is left disappointed when all of the soldiers begin fighting with each other over the meat, apologizing to his fellow officers for wasting so much of the Scouts' budget on the meat. His disappointment only mounts as the night proceeds, dejectedly grumbling about the soldiers' misbehavior as they begin physically attacking each other.
The following day, all soldiers are ready at sunset. Harold and other high-ranking soldiers salute to members of the other branches and head to the Wall. However, they are met with unexpected fanfare from Trost District's citizens, led by Flegel and the Reeves Company. Having intended to keep their departure a secret to the public, all of the soldiers are left bewildered as to how the word spread, and Harold reveals that he bought the celebratory meat from Flegel. Their conversation is interrupted by Erwin, who begins cheering as well before ordering the scouts to begin their final mission to reclaim Wall Maria.
After successfully sealing the hole in Wall Maria, the scouts are ambushed by the Beast Titan and its forces. On Erwin's orders, Harold accompanies Squad Levi and Squad Hange to engage the Armored Titan. After managing to seemingly take down the Armored Titan, the soldiers flee the area after noticing a barrel fly over the Walls. When it does not immediately explode, Hange orders the group to go and finish off Reiner. However, as they are returning to the Armored Titan they are caught in the blast from Bertholdt's Titan transformation.