Stephen A. Miller, 41, of Highland Park was arrested and charged Wednesday, the state's attorney's office said.
The Lake County Sheriff's Office Tactical Team executed a search warrant at Miller's home Wednesday.
Several electronic devices were seized, officials said.
SEE ALSO: North suburban high school teacher charged with transporting child pornography: U.S. attorney
"Protecting children is one of the highest priorities of our office. Our Cybercrimes Division, special investigators, and law enforcement partners continue working tirelessly to uncover critical evidence in cases involving the exploitation of children. We will continue investing in the tools, resources, and partnerships necessary to hold offenders accountable," Lake County State's Attorney Eric Rinehart said.
Miller will be held at least until a detention hearing Monday.
A spokesperson for Northwestern said the school does not comment on personnel matters.