Dr. Thomas Stockmann, Medical Officer of the Municipal Baths.
Mrs. Stockmann, his wife.
Petra (their daughter), a teacher.
Ejlif & Morten (their sons, aged 13 and 10 respectively).
Peter Stockmann (the Doctor's elder brother), Mayor of the Town and Chief Constable, Chairman of the Baths' Committee, etc.
Morten Kiil, a tanner (Mrs. Stockmann's adoptive father).
Hovstad, editor of the "People's Messenger."
Billing, sub-editor.
Captain Horster.
Aslaksen, a printer.
Men of various conditions and occupations, a few women, and a troop of schoolboys—the audience at a public meeting.
The action takes place in a coastal town in southern Norway.