Katie Matlin is a graduate of Degrassi Community School's Class of 2012. She works hard and plays harder. Being gifted with athletic skill, and striking, fresh-faced looks, she made herself a force not to be reckoned with. Her years of mastering the bicycle kick kept her from learning how to cake on the make-up. She is driven and thorough when it comes to academics and extracurriculars. She is also blunt and direct when talking to other girls, even her fun-loving BFF Marisol. However, when it comes to talking to boys, or about matters of the heart, she clams up. She is often shown to be insecure about many things, such as her body and her relationships.

After tearing her ACL, Katie became addicted to painkillers, went to rehab for her addiction, and had a messy break-up with then-boyfriend Drew Torres. This resulted in not only an indefinite hiatus from sports, but also a newly-found edginess, sharp black hairstyle, and a revamped personality. Katie also began seeing new people, as well as planting a garden at Degrassi as a new hobby. She transformed into a nicer, sweeter, and better person. Katie is Maya Matlin's supportive older sister. She is best friends with Marisol Lewis, and also friends with Clare EdwardsMo MashkourEli GoldsworthyAdam Torres, and ex-boyfriend, Jake Martin. She is on good terms with former enemy Bianca DeSousa. She was also on good terms with Maya's ex-boyfriend, Campbell Saunders before his death. Katie is enemies with Mike Dallas, Luke Baker, and the rest of the Ice Hounds. She is portrayed by Chloe Rose.