The protagonist of the play is Annie Sullivan, a headstrong and determined Irish American teacher from Boston. She is 20 and a recent graduate of the Perkins School for the Blind, where she went to study after spending time at the state almshouse with her brother Jimmie, who died as a child. Since her brother’s death, Annie “hasn’t loved a soul” (17). Annie’s journey toward opening her heart to love again is a major story arc within the play.

When Annie arrives at Ivy Green, she warns Kate not to underestimate her abilities as a teacher because of her youth. Annie has three advantages that will serve her on the job: she is well-educated on the material that she will be teaching Helen, she has energy to keep up with Helen because she is young, and she was blind as a child. Through multiple surgeries, much of her vision was restored. However, she wears darkened glasses due to light sensitivity. These glasses serve as a reminder to the reader (or audience) that Annie can empathize with Helen on a level beyond that of which her parents are capable. She understands how important language is for Helen and will fight to help her learn it.