Thomas’s practical and protective wife, who prioritizes her family's safety and stability amidst the turmoil surrounding her husband. She balances her husband's idealism with her own sense of reasonableness.

Thomas and Katherine's independent and strong-willed adult daughter, who works as a schoolteacher and supports her father's quest for truth. She is frustrated by the restrictions in her teaching environment.

The two younger children of the Stockmann family who are spirited and sometimes rebellious. They often get into trouble but exhibit a youthful embodiment of their father's independent spirit.

The mayor of the town and Thomas's brother, who is influential and protective of the town’s economic interests. He is involved in the politics surrounding the Baths and has a complex relationship with his brother.

Katherine's adoptive father and the owner of a local tannery, known for his wealth and focus on preserving his economic interests. His views on the pollution controversy are influenced by his business stakes.

The editor of the People’s Messenger, the town’s primary newspaper, who initially supports Thomas for his own political ends. He is portrayed as politically radical but also strategic in his decisions.

An associate at the newspaper who engages in performative radicalism and seeks a position in local government. He is involved in the newspaper’s activities and has connections to political developments.

The owner of the printing press and a prominent community member who advocates for moderation. His influence and alignment with public opinion affect the town’s stance on issues concerning the Baths.