With 20 years of age, Anne showed ingenuity when she was  teaching a blind and deaf child called Helen Keller.
She wanted to help Keller making associations between words and physical objects. Many time before she was isolating Keller from her own family  in order to better educate and also  Sullivan began working to teach Keller how to communicate with the outside world.

One day when she was doing  one lesson, the finger of Keller spelled the word "water" . Finally Keller made her first major breakthrough: when she was connecting the concept of signed language with the objects around her. This thing, however was a very important advance because never she was relating nothing.

Thanks to Sullivan's instruction, Keller learned nearly 600 words, most of this words where multiplication tables, and how to read Braille . Keller became a celebrity because of some reports where she was meeting the likes of Thomas Edison, Alexander Graham Bell, and Mark Twain.

Sullivan decided that Keller could benefit from the Perkins School's program, and the two spent time there.  They also sought aid for Keller's speech at the Wight-Humason School in New York City. When Keller's family could no longer afford to pay Sullivan or manage Helen's school costs, a number of wealthy benefactors stepped in to help them defray their costs.

Despite the physical strain on her own limited sight, Sullivan helped Keller continue her studies at Radcliffe College in 1900. She spelled the contents of class lectures into Keller's hand, and spent hours conveying information from textbooks to her. As a result, Keller became the first deaf-blind person to graduate from college.