William Blaine Richardson III was an American politician, author, and diplomat who served as the 30th governor of New Mexico from 2003 to 2011. He was also the U.S. ambassador to the United Nations and energy secretary in the Clinton administration, a U.S. congressman, chair of the 2004 Democratic National Convention, and chair of the Democratic Governors Association.

The United States secretary of energy is the head of the United States Department of Energy, a member of the Cabinet of the United States, and fifteenth in the presidential line of succession. The position was created on October 1, 1977, when President Jimmy Carter signed the Department of Energy Organization Act, establishing the department. The energy secretary and the department originally focused on energy production and regulation. The emphasis soon shifted to developing technology for better and more efficient energy sources, as well as energy education. After the end of the Cold War, the department's attention also turned toward radioactive waste disposal and the maintenance of environmental quality. Former secretary of defense James Schlesinger served as the first secretary of energy. As a Republican nominated to the post by Democratic president Jimmy Carter, Schlesinger's appointment marks the only time a president has chosen a member of another political party for the position. Schlesinger is also the only secretary to be dismissed from the post. Hazel O'Leary, Bill Clinton's first secretary of energy, was the first female and first African American to hold the position. The first Hispanic to serve as Energy Secretary was Clinton's second energy secretary, Federico Peña. Spencer Abraham became the first Arab American to hold the position on January 20, 2001, serving under the administration of George W. Bush. Steven Chu became the first Asian American to hold the position on January 20, 2009, serving under president Barack Obama. Chu was also the longest-serving secretary of energy and the first individual to join the Cabinet after having received a Nobel Prize.