During an interview with Waukesha County detectives, Solum admitted to engaging in sexual activity with the girl at AHS, the complaint said.
He told police the girl said she was 14 — in fact she was 13 — after their second sexual encounter, but said he believed she was 20 based on an online dating profile he saw for her.
Solum was charged with three counts of using a computer to facilitate a child sex crime and two counts of second-degree sexual assault of a child, all felonies.
Court records show he pleaded no contest to one count of either charge as part of a plea agreement.
The remaining charges were dismissed but read into the court record.
Judge Jeffrey Conen sentenced Solum to five years in prison, and seven years of extended supervision, on each count, but ordered Solum to serve the sentences concurrently.
A Milwaukee man charged a little more than a year ago with sexually assaulting a then-13-year-old girl twice in 2016 in parking lots at Arrowhead High School has been sentenced to five years in prison.