While he was a deputy for the sheriff's department, he encountered several supernatural predicaments but didn't believe in it. They ranged from encountering Ennis, questioning Chris Argent about a body, and finding a mutilated Julia Baccari.
His wife, Claudia, was sick with frontotemporal dementia which deteriorated her mental state.
While at the scene of a wreck, a woman who was critically injured told Stilinski that if he want to see his wife to go now. Instead, he with the woman until she died. He arrived at the hospital to find his wife dead before he got there, missing the chance to say goodbye to her.
Only after his son becomes involved with the supernatural and tries to explain it to him did finally start to believe in it. Since then, he has been a pivotal, and at times reluctant, ally of Scott's Pack.
He learns about the supernatural through Stiles and nearly becomes a sacrifice of the Darach.
He becomes frustrated with the cover ups that are required with his son's and friends incidents.
- “Not exactly, or no? Because when it comes to law, there's a fairly large divide between not exactly and no. Like, if 'not exactly' were sitting in this chair, then 'no' would be somewhere in the middle of the pacific ocean, drowning next to my career. So what's it gonna be, huh? Not exactly or no?” — Sheriff to Jackson Whittemore in Venomous.
- “Are you crazy?” — Sheriff to Stiles Stilinski in Fury.