Luke Matthews was portrayed by Andy Chambers. There is some confusion regarding his name as Luke is sometimes credited as "Luke Cassellis" on cast lists online, but is referred to as "Luke Matthews" on the show.
Luke Matthews is an occasional character in Degrassi Junior High and Degrassi High who became known for drug use and provision. He provided the drugs that caused Shane McKay's serious injury and left him brain-damaged. He was friends with Yick Yu.
In He Ain't Heavy..., Luke tries out for the basketball team.
In Taking Off (1), he offers Shane acid before they get into the concert. The next day when Shane goes missing, Luke lies to the police and tells the officer Shane wasn't doing drugs and that he doesn't know anyone who uses drugs.
In Taking Off (2), Caitlin Ryan asks Luke if he knew what happened to Shane, but he says he doesn't. Mr. Raditch then asks the class if they have any information regarding Shane, they should come forward to the police. The police then call Luke out of class to tell him that they found Shane under a bridge. They call him out on his bluff, revealing that many witnesses have come forward stating that Shane was on drugs. Luke confesses that Shane might have taken acid.
In Making Whoopee, Luke asks Tim O'Connor how Shane is doing in the hospital. Tim says that he is still in a coma and Luke should go see for himself. Luke tells him that they "weren't that close," and that he hates hospitals. Tim walks away angry. Later, Luke hands Tim a card to give to Shane. Tim tells Luke to give Shane the card himself. Tim tells Luke that if he had stayed with Shane that night, he probably wouldn't be in the hospital. Luke yells that he already knows that and feels guilty about it and walks away. Tim picks up Luke's card off the ground.
In Bye-Bye, Junior High, Luke brings a disabled Shane to the end of the year dance.
In Nobody's Perfect, Mr. Walfish pairs Luke and Kathleen up for a Shakespeare recitation of Romeo and Juliet for English class. Luke doesn't want to bother rehearsing, but Kathleen convinces him to stay after school and practice. Kathleen's abusive boyfriend, Scott, finds them and kicks Luke out of the room.
In Little White Lies, Melanie invites the whole class to her party, including Luke, whom she has a crush on. Diana tags along with Luke and Yick when they go outside to smoke at school. They all get in trouble when Ms. Avery catches them. Melanie is disappointed when Luke doesn't show at her party. Arthur tells her that he and Yick are home playing video games.
In All In a Good Cause, Arthur feels left out when his best friend Yick is always ignoring him to hang out with Luke. Luke teases Arthur for being too straight-laced and nerdy and Yick laughs along. At the end of the episode, Luke is impressed when Arthur and Yick toilet-paper Mr. Raditch's house.
He doesn't get any main roles in season 5 either.
In The All Nighter, he invited Yick, Joey and Arthur to his house to play poker all night. At this time, he still didn't care too much for Arthur. Then when Yick stood up for Arthur, and told him to give him a chance.Knowing Arthur was rich, and that he never play poker before, he was certain he would cream him and win a lot of money. Ergo he happily invited him over. Then to his surprise Arthur did incredibly well and won all of his money and soon his shirt too. When the game was coming to an end Luke, tried lying about his cards as he long could. This was to see if Arthur would eventually give in and fold, however eventually Luke gave up and folded too. When Arthur treated him and the others to pizza, Luke peeked at his cards, when he answered the door. He then found out he was bluffing too and was also waiting for him to give up and fold. They all broke out into laughter about how a nerd like Arthur beat him at poker and they all had the pizza and had a good time. Soon Arthur earns his respect.