Garrett Clegg is the husband of Kelly Enya Clegg. He is a combat veteran and a vigilant disaster relief volunteer.
Due to an IED blast during his deployment, Garrett has PTSD, traumatic brain injury, and is missing half of his right forearm. He also has burn scars over a large portion of his body, including his face. He walks with a slight limp and speaks with a rasp due to damage to his throat. He only has partial vision in his right eye. Later, it is revealed he is also missing his right leg from below the knee.
Garrett is first seen at the Grunwald Museum during the Veterans Day celebration, where Kelly listens to him telling the story of Grunwald's folklore to a group of children. She remarks on his gift for storytelling. He also demonstrates an imitation of a wolf howl that sounds real due to years of practice.
Despite Kelly's insistence, Garrett does not wish to stay in town. He returns to his work at the Louisiana gulf coast as soon as he is finished telling the story to several groups.
He next speaks to Kelly on the phone the next morning, when she is giving him a brief summary of the ordeal with Emma Lee Hagen.
Kelly discusses Garrett with Chester Cotton, revealing that her parents had nearly convinced her to divorce him during his deployment, which became complicated when she discovered she was pregnant. She lost the baby early on, however, and continued to consider divorce until she was notified of his combat injury. She notes that his injury, Mickey's death, and his learning of the miscarriage shortly afterward seem to have compounded into an overwhelming amount of stress for him. Garrett seems to cope by throwing himself into the volunteering work, staying away from Grunwald as much as possible, but Kelly has not thought again of divorce. Cotton reveals that he also has a combat injury, leading Kelly to consider getting the two of them in touch.
After Kelly is overwhelmed from reading the letter written by Muriel Greaves, Maggie and Gordon encourage her to take a cue from the myth and call her husband if she cannot face this alone. Kelly is skeptical, but to her surprise, Garrett drops what he is doing and rushes back to her side once he hears the full story.
Garrett meets with his parents on the way to his home, picking up a photograph of the forest boy which he gives to Kelly. He then prepares to travel into The Green Ravine River Valley after dark to rescue Laylah Flaherty. He brings out a .45 pistol, but he gives it to Kelly as he believes his injuries have rendered him useless with a handgun. Instead, he arms himself with his shotgun as well as a large knife and a roll of bandages.
After leading Kelly into the woods, Garrett locates the boy. He makes a futile attempt to kill the Grim Halberdier, and he is amazed when Anvilback and then Momma Kodi appear to do battle in the river. He spots Laylah across the river and plans to use the fight as a distraction to sneak across the bridge.
However, Drag-Belly and Anvilback get the upper hand against Kodi, convincing Garrett to intervene. At Kelly's suggestion, he creeps up to the river and uses his imitation howl to fool the beasts into thinking King Firehide has arrived. Drag-Belly turns his attention to the humans, allowing Kodi to seize the advantage and kill Anvilback.
Drag-Belly attacks Garrett, whose efforts to defend himself result in his shotgun being jammed. While he is trying to clear the jam, Drag-Belly pulls off his prosthetic leg. Kelly gets Drag-Belly's attention, allowing Garrett to clear the shotgun. He tosses her the loaded weapon, which she fires down the crocodile's throat. Drag-Belly's thrashing tail sends Garrett flying into a tree, dislocating the shoulder of his already damaged arm and taking him out of the fight.
Garrett keeps his wits about him after his injury, giving directions to both Kelly and the boy. Kelly drives him to the hospital, where they set his shoulder. His parents drop by with information obtained from the library archives, which he keeps for Kelly. He is enraged when David Branchett and Joe Collins arrive to arrest Kelly, but he cannot do anything about it.
That afternoon, Garrett comes to the jail to bring Kelly the archive files. Cotton arrives, and the two have a face-to-face conversation at last. Cotton mentions that Kelly had been relieved at her miscarriage because it gave her an "out" for divorce. Garrett knows this, but he feigns shock and anger as his parents had sussed out that this was the reaction Cotton was hoping for. He pretends to storm out before hiding so he can follow Cotton after he takes the boy.
After his parents get Kelly out of jail and reveal the deception, Garrett meets up with her and apologizes for his part in it. The four come up with a plan to lure the townsfolk into the woods after dark. Garrett's part of the plan is to call the police back and confirm the rumors that Kelly herself had inflicted Garrett's broken arm. He then accompanies the cops into the woods, where the citizens arrive at the clearing in time to witness the emergence of the Grim Halberdier.
When David Branchett's nerves get the better of him, Garrett takes Angus Branchett's revolver away from him. Garrett demonstrates he still has skill with a handgun by shooting the Grim Halberdier in the face, saving Kelly. He tries to deliver a second shot at point-blank range, but is knocked down for his trouble. These actions win him the respect of Kelly's Mother at the conclusion of the fight.
When Ethan refuses to flee Grunwald during Eld Stagger's attack, Garrett forces him into Kelly's car. Rather than drive away, however, Garrett retrieves his shotgun. He is too injured to use it, so he gives it to his father instead. Stagger drops them both from several feet in the air, but Garrett manages to avoid injury for once.
Garrett, like Kelly, is pinned in place by the power of the Leviathan, and Stagger prepares to kill them both with a single strike. At the last moment, he comes to the same realization Kelly does, but he lets her explain it. He then helps encourage Ethan to unleash his true power and kill Stagger.
After the battle, Garrett promises he will find a new mission that will allow him to stay in Grunwald with Kelly.
He is last seen in the final chapter, with new prosthetics, walking with his wife and their newly adopted son to take him to Vacation Bible School.
- Garrett's name is a reference to the Pink Floyd lyric "Corporal Clegg had a wooden leg."
- An idea that was considered but never made it into the final version was that Garrett threw away a full-ride football scholarship to join the military.