In 1971, Harris was named to the board of directors of IBM, becoming the first Black American woman to sit on a Fortune 500 company's board of directors. In addition, she served on the boards of Scott Paper, the National Bank of Washington, and Chase Manhattan Bank. Upon her appointment to the Chase Manhattan board, she observed: "The demands on the small pool of blacks allowed to develop in the last 300 years is too great. What has to happen is that this pool must be increased, and that's something that big corporations can help to do. I'm a first on many boards, but I'm not going to be content to remain the only black, or the only woman."