Joe was born in Hollywood, Florida to Jewish American parents and went to Hebrew school. His father is a cardiologist. Trohman grew up in South Russell, east of Cleveland, Ohio. He lived there for 12 years and attended Chagrin Falls Schools, playing the trombone in the school band until he picked up guitar later in his secondary school years. He moved to Winnetka, Illinois, a suburb of Chicago when he was around 12 years old. He attended Washburne Middle School, where he participated in various bands for fun. After Washburne, he attended New Trier Township High School, where band mate Pete Wentz also went to school. During his high school years he was part of the audio visual club, New Trier Network, as well as briefly playing bass in Arma Angelus with Fall Out Boy's Pete Wentz on vocals