Ray Davis, a radio broadcaster who was the host of bluegrass music shows for more than 60 years and played a key role in making the Mid-Atlantic a leading center of traditional Appalachian folk music, died Dec. 3 at a hospital in Frederick, Md. He was 81.

The cause was leukemia, said his wife, Nona Davis.

As a boy growing up on Maryland’s Eastern Shore, Mr. Davis had aspirations of being a broadcaster and practiced speaking into the resonant water barrels on his family’s chicken farm. After landing his first job in radio at 15, he soon began to champion the music that later became known as bluegrass.

He spent more than 35 years at WBMD-AM in Baltimore, broadcasting for much of that time from a used-car lot. His sponsor, the owner of Johnny’s Used Cars, was such a dedicated fan of country music that he built Mr. Davis a studio next to the Oldsmobiles and Chevys.

“Yes, indeed, folks,” Mr. Davis said in a broadcast from December 1963, “the Stanley Brothers are coming to you live today from Johnny’s at 4801 Harford Road in Baltimore. We’ve got Santa Claus with us, we’ve got good food for the family, candy for the young folks and we’ve got for you right now, Ralph Stanley.”

Ray Davis, host of “Bluegrass Country” on Washington’s WAMU-FM and fixture in the world of bluegrass music. (WAMU)

Patsy Cline, Ernest Tubb, Lester Flatt and Earl Scruggs were among the other acclaimed performers who appeared on Mr. Davis’s show. He went on to become a fixture on the bluegrass scene nationwide as a promoter of concerts and festivals, where he often acted as emcee.

After joining Washington’s WAMU-FM in 1985, Mr. Davis broadcast his “Bluegrass Country” program every weekday afternoon for 16 years. It generated the second-highest amount of donations from listeners during the station’s fundraising pledge drive, but in 2001 the station cut back his schedule, prompting a backlash among some listeners.

His program continued to be heard overnight, online and over another radio outlet affiliated with WAMU until his retirement in 2013 after 65 years on the air.

Raymond Herbert Davis was born May 2, 1933, in Wango, Md. He was drawn from an early age to radio.

“They had Bill Monroe on, and it was the kind of music that just turned me on,” Mr. Davis said in a 2008 interview with NPR. “I was just a young boy, but it was a banjo, fiddle and mandolin, and they were singing that high, lonesome sound and I was hooked, and I have never let it go since that day.”

He was 15 when he began working as an announcer with a station in Dover, Del., reading the news, weather and promotional material. He worked briefly in Nashville and Miami, where he was a sportscaster. Music was always his primary interest, however, and Mr. Davis had his first country-music program in Baltimore while still in his teens.

In the 1960s, he launched a record label, Wango, named for his home town. He recorded most of the music in his basement studio, first in Glen Burnie, Md., and later in Falling Waters, W.Va., where he lived for the past 20 years.

“I very rarely overdub because I want the music to have a live feel to it,” Mr. Davis told Radio World, an industry publication, in 2008. “There is just better chemistry this way. If everyone is in the song together, they feel it and it shows up on the record.”

His marriages to Joan McComas, Eileen Heller and Caroline McCeney ended in divorce. Survivors include his wife of 25 years, Nona Alimo Davis of Falling Waters; a son from his first marriage, Ray Davis of Silver Spring, Md.; six children from his second marriage, Duane Davis of New Freedom, Pa., Jimmy Davis of Spring Grove, Pa., Susan Fidler of Bel Air, Md., Cheryl Avila of Gettysburg, Pa., Martha Riddell of Miami and Melanie Sita of Fredericksburg, Va.; four stepchildren, Harry Alimo, Rocco Alimo and ReEtta Peterson, all of Cape May, N.J., and Theresa Papale of Ocean City, Md.; two brothers; a sister; 16 grandchildren; and 12 great-grandchildren. A son from his second marriage, Raymond Davis, died in 1997.

In the 1950s, Mr. Davis worked at XERF, the same high-powered 250,000-watt “border radio” station in Mexico that made Wolfman Jack a celebrity DJ. In addition to playing music, Mr. Davis became a skilled advertising pitchman at the station, selling such things as baby chicks and radioactive dirt collected from nuclear test sites.

“That offer didn’t last long,” he recalled in the NPR interview, “but neither did the people that used it.”