Theodora Erikson was born in Oscoda, Iosco County, Michigan, near the shores of Lake Huron on 22 January 1907. She was the seventh of nine children of Charles and Natale Erikson, who had come to America from Sweden in 1882. "Teddy" earned a Life Certificate in teaching from Ypsilanti State Teachers College in Michigan before she was twenty years old, and taught in several rural and urban communities, including Alcona County, Michigan.

She met and married Ray Cooper, a physician, and they took up residence in Albuquerque, New Mexico. In Albuquerque, Teddy earned a Bachelors of Science degree in education from the University of New Mexico in 1948. She began teaching for the Albuquerque Public Schools. She was assigned to the elementary school at the semi-secret atomic weapons installation in southeast Albuquerque, known as Sandia Base.

Sandia Base was the follow-on to the Manhattan Project and thus was the nation's premier nuclear weapons base throughout most of the Cold War. At Sandia Base Elementary School, Teddy Cooper taught the children of highly trained military personnel and civilian nuclear scientists. She spent twenty-five years at Sandia Base Elementary School before retiring.

Mrs. Cooper became very popular with her students, her colleagues, and the Sandia Base parents. She frequently teamed with her friend and colleague, Nathalie Harshman, to team-teach various subjects. Around the state of New Mexico, she was regarded as an expert in the teaching of arithmetic, and frequently was called upon to attend teacher conferences to demonstrate her techniques. She also enjoyed and excelled at the teaching of reading.

Teddy Cooper was active in the Association of American University Women and the New Mexico Council of Teachers of Mathmatics. She founded the Junior Red Cross chapter at Sandia Base Elementary School. Her students recall and describe her as especially empathic with a great sense of humor.

On Friday, November 22, 1963, Mrs. Cooper had dismissed her class for lunch. When the students returned, most had already heard the tragic news and were not surprised to find their fourth grade teacher weeping openly over the murder of the President of the United States. The President had visited Sandia Base less than a year earlier and his motorcade had passed down Wyoming Boulevard which ran directly adjacent to the school's front lawn. Over the next several weeks, Mrs Cooper made special efforts to help her students cope with the emotional depresssion that had settled like a fog over the entire nation.

Teddy's husband, Ray, died an early death and she never re-married. They had one child, Foster Cooper.

Theodora Erikson Cooper died on Sunday, June 4, 2006. She was 99 years old. She is buried in Oscoda, Michigan.