Mrs. Alving lives with her maidservant, Regina, in a mansion in Norway's countryside. She married her late husband, Captain Alving, at her relatives' suggestion, but she had a horrible marriage. She ran away once, to Pastor Manders, to whom she was attracted, but he made her return to her husband. She endured her husband's debauchery but sent away their son, Oswald, at the age of seven, with the hope that he would never discover his dead father's immorality. (His father died ten years before the start of the play.) Mrs. Alving has established an orphan asylum (an orphanage) to memorialize his death, and it is schedule to be dedicated the following day. She doesn't want anyone to doubt that he was a good and honorable man. At the same time, she is a free-thinking woman and feels compelled to tell her son the truth about his father.
Pastor Manders is a local priest from the nearby town. He often lectures others about morality and religion. Sometimes, his financial dealings regarding the orphanage seem suspect, and he is also quick to bend to public opinion. He believes that Mrs. Alving should not have abandoned her husband and should not have sent her son into the world at such an early age. He is easily shocked.
At the play's start, Oswald has come home to spend the winter with his mother. He has most recently been in Italy, living a relatively bohemian life. He is also a promising painter. Pastor Manders believes that he has strayed from what is moral and also finds him reminiscent of his father. Oswald is by nature idealistic. Recently, however, he has felt a profound listlessness, for which he blames himself. He also shows a romantic interest in Regina.
Regina is Mrs. Alving's maidservant. She is believed to be the daughter of Jakob Engstrand, a carpenter, and the late Johanna, Mrs. Alving's former maid. In fact, she is the illegitimate daughter of Johanna and Captain Alving. She only learns this at the end of the play. Throughout the play, she resists her father's dubious affection and takes pride from working in Mrs. Alving's home. She seems to return Oswald's affection, even peppering her speech with French, which she has learned in the hope that Oswald will take her to Paris. However, she is careful not to overstep the bounds of what is proper.
A carpenter with a deformed leg, Jakob married Johanna when she was pregnant with Captain Alving's child. The daughter was Regina. At the start of the play, he is working on the orphan asylum meant to memorialize Captain Alving. He wants to use the money he is saving to open an "establishment" for sailors. When speaking to Pastor Manders, whom the hypocritical Jakob always tries to please, he describes the establishment as a place to reform sailors. But when he describes it to Regina, it sounds like a high-class saloon. He is an alcoholic.
Captain Alving died ten years prior to the start of the play. He was a very famous man with a good reputation, and before he died he was made a chamberlain. He never appears in the play but is often referred to. According to Mrs. Alving's account, he was, in fact, a lazy, dissolute man.
Johanna was the Alvings' servant and gave birth to Regina after being forced by Captain Alving to sleep with him. She is dead and never appears on stage.