He was portrayed by Stephen Lunsford.
Matt was a student at Beacon Hills High, a photographer and was also on the lacrose team. He stalked Allison throughout season 2 and was the secondary antagonist of season 2. He was the Kanima's first Master. In the second season premiere, "Omega", he takes pictures of Allison at Kate Argent's funeral, but is accosted by Gerard Argent who destroys his camera's memory card. When he was photographing Allison, Lahey had got in one of his shots. Matt felt an unbelievable rage for his near-drowning years earlier and wished that Lahey was dead. The following morning he found out Lahey was dead. In episode "Shape-Shifted" he lends Jackson a night-vision camera for Jackson to record his expected full moon transformation. He'd spied on Jackson using his camera and witnessed his transformation into the Kanima. He and the Kanima touched hands seemingly by instinct. Through a supernatural bond that formed between the two of them he saw that Jackson had killed Lahey for him and Matt became Master of the Kanima. He used the Kanima to murder all members of the swim team who were involved in the incident, except for Jessica whom he killed directly.
He notices a strange flash in each of his photo shots of Scott McCall in the episode "Venomous" (caused by Scott's uncontrolled werewolf eyes which were triggered by the flash of his camera). In "Restraint", he steals a translated portion of the bestiary depicting the Kanima from Allison's tablet. He takes Allison out on a date to a warehouse party in "Raving", unaware that Allison was only using him to throw her parents off her back about staying away from Scott, where he kisses her, but Allison finds out he's a stalker upon finding his many inappropriate photos of her. In "Party Guessed", she confronts him about his photos, but when his behavior annoys her, she judo-flips him.Later on, he is thrown into the pool, which causes him to go into a panic, raising Scott and Stiles' suspicions seeing as to how the kanima is afraid of water, and especially since Jackson helps him out of the pool. He is seen, by Scott, with Jackson in his Kanima state revealing Matt's the Kanima's Master.
In 2006, nine-year-old Matt had gone to Isaac Lahey's house to trade superhero comic books with him. The swim team of Beacon Hills High at that time were having a pool party at the house and drinking alcohol to celebrate their winning the state championship. Matt was thrown into the pool by Camden, Isaac's older brother, despite yelling that he can't swim, resulting in him almost drowning. He was resucitated by Coach Lahey who berates him about not knowing how to swim and demands he tell no one what happened. Matt obliged keeping the incident secret, causing himself trauma and having irregular nightmares where he's drowning.
In "Fury", at the Sheriff's station, Matt has Jackson murder all the deputies on night shift, destroys all the evidence linking him to the murders and takes Scott, Stiles, Derek, Stilinski and Melissa hostage. He reveals he knows all about the supernatural events occurring and demands Scott hand over the bestiary. He needed answers as to why he was beginning to transform into the Kanima, but Derek silently realized Matt had broken the rules of the Kanima. The Master is to use the Kanima to kill murderers, while Matt had him kill innocent people and he had killed Jessica Bartlet directly. The hunters attack the building and in the struggle between the Argents, Jackson, and Scott and Derek, Matt escapes butGerard kills him by drowning him, using this opportunity to become the Kanima's new Master.