The Milwaukee Journal Sentinel reports the fire was reported Saturday night by a police officer who saw it while on patrol.
Firefighters arrived to find flames had taken over the home. The roof collapsed shortly after firefighters arrived, then part of the first floor collapsed into the basement.
Crews found the victim inside. The person has not been identified and the cause of death is being investigated.
The cause of the fire is also being investigated. North Shore Fire/Rescue says it appears the blaze started in a first-floor living room. Fire crews did not see any smoke detectors in the house.