Eleanor Vance, the protagonist is the most developed, rounded character. Eleanor, thirty-two, has spent most of her adult life caring for her invalid mother, and she is shy, repressed, and looking for her identity. Her fatal summer stay at Hill House proves to be her quest for a home, so that she becomes another one of the ghosts at the novel's end.
Dr. Montague is a genial academic authority figure, who sets up the 'ghost hunt' in order to solve Eleanor's mental problems.
Theodora provides a clear, emphatic foil to Eleanor, since she is decidedly flamboyant, attractive, bohemian, and unrepressed.
Luke Sanderson, a young wastrel, is the heir to "Hill House." Similar to Theodora in several strains of his character, less straight-laced than Dr. Montague or Eleanor, he provides comic relief, as something of the glib seducer.
The two caretakers, Mr. and Mrs. Dudley, who refuse to stay near Hill House at night. The blunt Dudleys are the source of the novel's sparse comic relief.
All these characters encounter the house, which had been built by Hugh Crain, itself a kind of character since it is such a dominant setting alive and moving with ghosts and unexplained negative activity.