A medical doctor who serves as the chief medical officer for the town's newly built medicinal Baths. Having recently confirmed his suspicions that the Baths' water supply is dangerously contaminated, he eagerly prepares to share the news, expecting the town to hail him as a hero. He is a highly principled and scientifically minded man, but his deep idealism leaves him oblivious to the economic and political realities driving the local government.

Dr. Thomas Stockmann's wife and the adoptive daughter of wealthy tannery owner Morten Kiil. She is a traditional and highly pragmatic woman who prioritizes her family's safety and social standing above her husband's abstract ideals. She frequently acts as a moderating force in the household, attempting to shield her family from the unpredictable consequences of Thomas's political blindness.

The adult daughter of Thomas and Katherine, who works as a teacher at the local school. She shares her father's fiercely independent spirit and uncompromising dedication to the truth. She finds her job deeply frustrating, as she is forced to instruct her students in widely accepted societal values that she fundamentally opposes.

The town mayor, chairman of the Baths committee, and Dr. Thomas Stockmann's older brother. He is a calculating authority figure who believes individuals must subordinate themselves strictly to the community's leaders. He is fiercely protective of the town's economy and his own prestige, quickly bristling at any public actions Thomas takes without his direct approval.

Katherine's adoptive father, known around town as "The Badger." He is a wealthy but miserly tannery owner whose facilities sit near the town's water supply. He possesses a strong distrust of the town's local leadership and views scientific claims with deep suspicion, demanding visible proof of microbes before believing they exist.

The editor of the People's Messenger, the town's primary newspaper. He outwardly professes radical, progressive views and yearns to dismantle the local government's authority. He sees the controversy surrounding the Baths as a potential political weapon against the wealthy elite, though his paper remains heavily dependent on subscriber approval and financial backing.

The sub-editor of the People's Messenger. He projects a highly radical persona in casual conversation, proudly claiming to be a pagan who wishes to upend traditional society. Despite his loud revolutionary rhetoric, he harbors quiet, mainstream ambitions within the town's political structure.

The owner of the local printing press, president of the Householder's Association, and a prominent member of the Temperance Society. He wields significant quiet power in town because he represents the mainstream public consensus. His guiding political philosophy is strict moderation, meaning he prefers cautious agreement over disruptive truth.

A local ship captain who remains entirely uninterested in town politics. Because his livelihood and social standing do not depend on the local government or the economic success of the Baths, he operates outside the town's usual power dynamics, offering steadfast, practical hospitality to the Stockmann family.

One of Thomas and Katherine Stockmann's two young sons. He embodies his father's energetic, uncompromising spirit in a juvenile form, frequently testing boundaries and challenging authority figures at school.

The other young son of Thomas and Katherine Stockmann. Alongside his brother, he represents the new, impressionable generation growing up in the politically divided town, eager to emulate his father's independence.