Patricia Roberts Harris began her career as a lawyer and political adviser, even working as a director at IBM for a time. She also served as United States Ambassador to Luxembourg under President Lyndon B. Johnson, and was the first African-American woman to represent the United States as an ambassador. In 1977, she became the first African American woman named to a presidential cabinet (under President Jimmy Carter) and was the first woman to be part of the line of succession to the Presidency. She was 13th in line.

Source: https://en.wikipedia.org/wiki/Patricia_Roberts_Harris