Captain Keller runs a newspaper and is an editor in The Miracle Worker. In the first act of the play, Kate, Keller's wife, tells Helen (who is a baby at the time) that she will ask Helen's father (Captain Keller) to run an editorial in his newspaper about the miracles of modern medicine, as Helen has just been cured of acute congestion of the brain and stomach. Before running a newspaper in his town of Tuscumbia, Alabama, Captain Keller was an officer in the Confederate Army during the Civil War. In the play, he is portrayed as a commandeering sort of man who is convinced of the rightness of his opinions. He at first tries to control Annie Sullivan, Helen's teacher, but finds her unwilling to merely submit to what he says.

Captain Keller, a loyal Southerner who served in the Civil War, is a cotton plantation owner and editor of a local weekly newspaper who wields power both in the business world and in the domestic world. No domestic decisions are made without his approval. 

Perhaps it is his jounalistic background which causes him to be skeptical about the possibilities of his daughter Helen being able to learn from her new tutor, Anne Sullivan.  In the play "The Miracle Worker" Captain Keller acts as the antagonist to Anne, whom he first considers rude because of her candor and with whom he comes into conflict regarding the tutoring of Helen.  It is not until Anne brings Helen to the pump to make her fill the pitcher that Helen has emptied upon her, an experience that causes Helen to make connections between the hand-spelling and the person or thing, that Captain Keller gives Anne respect.