Born and raised in West Virginia, Johnson earned her Bachelor of Science degree in mathematics and French from West Virginia State College at the age of 19 in 1937. Following her graduation, she went on to become a teacher in Virginia’s public school system for the next two years. In 1939, Johnson was selected by Dr. John W. Davis, president of her alma mater, as one of three black students to integrate West Virginia University’s graduate program. While she enrolled to complete her graduate degree in mathematics, Johnson’s time at the university was short-lived, as she left to start a family.