Hahn's early childhood was marked by a relatively stable family environment, although the level of parental involvement in his scientific pursuits is somewhat debated. His parents divorced when he was relatively young.

The discovery of Hahn's radioactive experiment placed significant strain on his relationship with his mother, whose property was contaminated and subjected to an expensive cleanup operation. This strained relationship had a lasting impact on Hahn, with his mother dying the next year.

In his later years, Hahn reportedly experienced periods of isolation and estrangement from family members and friends. His struggles with substance abuse and mental health likely contributed to these difficulties. Public records indicate his father had to be contacted to formally identify the body.