Harold E. Davis Sr., 86, formerly of Rose Valley, a longtime arbiter and commissioner for the Federal Mediation and Conciliation Service, an Army veteran, and known as Mato Haha by the Eastern Band of Cherokee Indians, died Monday, Oct. 18, of sepsis and pneumonia at Arbor Terrace Willistown retirement community in West Chester.

Hired by the FMCS in 1968, Mr. Davis was one of the U.S. government’s first Black mediators, and he focused on labor, racial, sexual, age, and ethnic conflicts. He joined as the FMCS sought to diversify, and was recruited for “having the potential to develop into a good mediator after an intern period of growth.”

He went on to work in Washington and Philadelphia, and at conflict hot spots around the country until 1990. Among his negotiation assignments were the five-day Attica Prison riot in 1971 and the 71-day protest and occupation of the Pine Ridge Reservation near Wounded Knee, S.D., in 1973.

In 1979, he became the FMCS national representative for the experimental new area development initiative, which used “innovative actions” to address consumer, housing, environmental, discrimination, and interpersonal disputes.

Later, Mr. Davis served as an instructor for the FMCS, and he described his work this way in a 1982 paper called Training the Mediator: “Being able to facilitate parties in discovering nonobvious alternatives demands both substantive knowledge of the issue … and a broader ability to undertake imaginative analysis. … Probably the single most important characteristic of the good mediator is sensitivity toward others.”

Mr. Davis was also a candidate to become U.S. secretary of labor under President Jimmy Carter in the late 1970s. He supported the creation of a U.S. Department of Peace, and worked for the National Center for Dispute Settlement of the American Arbitration Association, and the Family Mediation Association.

Away from work, Mr. Davis often used the techniques he learned on the job to help veterans and others in need of conflict resolution. For him, listening to others was the key. “I met so many people who told me, ‘Your father saved my life,’” said his daughter Niki.

He spent seven years in the Army, four in Germany, before the Vietnam War, and became a captain.

In the 1990s, Mr. Davis discovered his Native American roots. Part Black Foot, Cherokee, African American, and Irish, he became a presiding elder of the Metis Nation of Delaware County, a member of the Eastern Band of Cherokee Indians, and adopted the name Mato Haha, which means Laughing Bear.

Called “the chief” by his friends, he bought a log house on Chestnut Lane in Rose Valley and built a sweat lodge in the backyard. He hosted classes and seminars about his Native American heritage and led or participated in many ceremonies, including the once-prohibited sun dance on the Rose Bud Reservation in South Dakota.

Born July 17, 1935, in Camden, Mr. Davis graduated from Camden Catholic High School in 1953. He almost became a priest but instead studied economics and received a bachelor’s degree from La Salle College in 1957 and a master’s degree from Clark University in 1958.

He married Helen Butler in 1958, and they had daughters Debbie, Niki, and Michaela and son Harold Jr. They divorced in 1980, and he married Carlota Velarde in the late 1980s. She died in 2008.

Mr. Davis suffered a stroke after an injury in 2000 and was partially disabled for the rest of his life. However, he regained his speech and other functions and was able to walk with a cane.

He spoke five languages, practiced aikido, and liked classical music, opera, the Rolling Stones, and Japanese culture. His family wrote in a tribute that he enjoyed “wine, women, and song … in that order!”

“I watched my father grow and transform throughout his life,” said daughter Niki. “He became my best teacher, and when we were together I soaked it up.”

In addition to his daughters and former wife, Mr. Davis is survived by four grandchildren and other relatives. His son and a sister died earlier.

A memorial service is to be held later.

Donations in his name may be made to STAG Vets Inc., 347 Horace Veal Rd., Milledgeville, Ga. 31061.