After serving in Congress and as governor of New Mexico, he practiced quasi-public and freelance diplomacy, often with considerable success.
Bill Richardson, who served two terms as governor of New Mexico and 14 years as a congressman before devoting himself to the cause of Americans who were being held hostage or who he believed were being wrongfully detained overseas, died on Friday at his summer home in Chatham, Mass., on Cape Cod. He was 75.
His death was announced by the Richardson Center for Global Engagement, which he founded. The cause was not given.
Under President Bill Clinton, Mr. Richardson was ambassador to the United Nations, succeeding Madeleine Albright in early 1997, and then secretary of energy, beginning in August 1998. He served in the House of Representatives, as a member of the New Mexico delegation, from January 1983 to February 1997 and as the chairman of the Congressional Hispanic Caucus.
Born in California (his mother had gone to Pasadena from Mexico City, where she was working, to give birth so there were would be no question about citizenship) and descended from William Brewster, a passenger on the Mayflower, Mr. Richardson was the nation’s only Hispanic governor during his two terms, from 2003 to 2011.
Representative Gabe Vasquez, a New Mexico Democrat, described Mr. Richardson in a statement as “one of the most powerful Hispanics in politics that this nation has seen.”
But his home-state popularity — he was re-elected in 2006 by 68 percent to 32 percent, a record margin in the state — did not translate into national office.
In 2008, Mr. Richardson mounted a short-lived campaign for the Democratic presidential nomination and then, despite having served in the Clinton administration, endorsed Barack Obama over Hillary Clinton.
After winning the presidency, Mr. Obama nominated Mr. Richardson as secretary of commerce, but he withdrew because of a pending investigation into allegations of improper business dealings in his home state. That investigation was later dropped.
After Mr. Richardson completed his second term as governor, he honed the quasi-public and freelance diplomacy skills that he had learned first in college and then on the staff of the Senate Foreign Relations Committee and when he worked on congressional relations for the State Department under Henry Kissinger.
His separate humanitarian missions on behalf of some 80 families won the release of hostages and American servicemen in countries hostile to the United States, including Iraq and Cuba.
In 2006, he persuaded President Omar al-Bashir of Sudan to free the Pulitzer Prize-winning American journalist Paul Salopek.
“I plead guilty to photo ops and getting human beings rescued and improving the lives of human beings,” he once said.
He helped negotiate the release of Michael White, a Navy veteran who was freed by Iran in 2020; flew to Moscow for a meeting with Russian government officials in the months before the release last year of Trevor Reed, a Marine veteran, in a prisoner swap; and worked on the case of Brittney Griner, the W.N.B.A. star who was held prisoner and later released by Moscow.
He also helped secure the 2021 release of the American journalist Danny Fenster from a Myanmar prison and this year negotiated the freedom of Taylor Dudley, who had crossed the border from Poland into Russia.
Mr. Richardson once described himself as “the informal under secretary for thugs.” He put it more diplomatically in a book published in 2013: “How to Sweet-Talk a Shark: Strategies and Stories From a Master Negotiator.”
“There was no person that Governor Richardson would not speak with if it held the promise of returning a person to freedom,” Mickey Bergman, vice president of the Richardson Center, said in a statement.
William Blaine Richardson III was born on Nov. 15, 1947, in Pasadena. His father, who was of Anglo-American and Mexican descent, was a bank executive from Boston who worked in Mexico for what is now Citibank and had been born on a ship en route to Nicaragua. His mother, Maria Luisa Lopez-Collada Marquez, who had been his father’s secretary, was the daughter of a Mexican mother and a Spanish father.
When Bill was 13, he was sent to the United States and attended Middlesex School in Concord, Mass. He earned a bachelor’s degree in French and political science in 1970 from Tufts University in Middlesex County, Mass., and a master’s in international affairs in 1971 from the Fletcher School of Law and Diplomacy at Tufts.
In 1972, he married Barbara Flavin, whom he had met in high school.
A complete obituary will appear shortly.