Liam was born in Cleveland, Ohio. He has performed in film, commercials, radio, print and in over 45 plays. His mother, Wendy Koeth is the producer and director of Stagecrafters Theatre and his father, Jamie Koeth, is a professional actor, acting teacher and director. Liam enjoys singing, skiing, reading, trumpet, and Sci/Fi and fantasy films. He is an avid video gamer and enjoys playing Dungeons & Dragons with his friends. He has earned his 3rd Degree Blackbelt in Tae Kwon Do and volunteers with special needs theatre students. He has a great love of animals, especially his two Rag Doll cats named Fluffy & Pippin. He played Dave Dahmer (Jeffrey's younger brother) in My Friend Dahmer opposite Anne Heche, Dallas Roberts, Ross Lynch and Alex Wolff directed by Marc Meyers. The film premiered at the Tribeca Film festival in 2017 and went on to great critical acclaim.