Former New Mexico Governor Bill Richardson, who also served as Energy Secretary and United Nations ambassador under the Clinton administration, has died at the age of 75, the Richardson Center for Global Engagement said in a statement quoted by CNN on Saturday.

Richardson died on Friday in his sleep at his summer home in Massachusetts, said the statement.

“He lived his entire life in the service of others – including both his time in government and his subsequent career helping to free people held hostage or wrongfully detained abroad. 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.

“The world has lost a champion for those held unjustly abroad and I have lost a mentor and a dear friend.”

Former President Bill Clinton and former Secretary of State Hillary Clinton, in a joint statement, hailed Richardson as “a devoted public servant and skilled diplomat.”

“Whether in an official or unofficial capacity, he was a masterful and persistent negotiator who helped make our world more secure and won the release of many individuals held unjustly abroad,” they said.

President Joe Biden similarly praised Richardson as “a patriot and true original.”

“Over the years, I saw firsthand his passion for politics, love for America, and unflagging belief that, with respect and good faith, people can come together across any difference, no matter how vast,” Biden said in a statement.

Richardson was born in 1947 in Pasadena, California. He grew up in Mexico City, Mexico. He earned a bachelor’s degree in political science and French from Tufts University in 1970 and a master’s degree from Tufts’ Fletcher School of Law and Diplomacy in 1971.

He married Barbara Richardson in 1972 and had one daughter.

Richardson was first elected to the US House in 1983, representing New Mexico’s Third District. He later served as US ambassador to the United Nations and secretary of energy before being elected governor of New Mexico in 2002. He served two terms in office and left in 2011.

In 2013 Richardson, who was a close confidant of US President Barack Obama and had endorsed him during the 2008 elections, called on Obama to release Jonathan Pollard, who at the time was in prison.