Danelo was an all–Los Angeles linebacker at San Pedro High School in San Pedro, California. Danelo was also a fullback and kicker at his high school. Because, at 5'10" and 200 lbs, he was undersized to be a major college linebacker, his father, former 9-year National Football League kicker Joe Danelo, taught him the position. Danelo became the first San Pedro High Pirate to play football at the University of Southern California in 30 years.