For 47 years, Charlie Waller was the voice and the rhythmic soul of modern bluegrass music, singing and playing guitar with the Country Gentlemen, the influential, widely traveled band he helped found in Washington in 1957. By the time he died at age 69 on Aug. 18 of a heart attack in his garden in Gordonsville, Va., he had helped transport bluegrass from the front porches of the Appalachians to college campuses, concert halls and the nightclubs of Georgetown.

In the 1960s, when Washington was the capital of bluegrass, the Country Gentlemen were the undisputed kings of what was called the "new-grass revival," recording albums that influenced younger musicians and launching bluegrass in a more popular direction.

If Bill Monroe, who died in 1996, was considered the father of the traditional bluegrass sound, Mr. Waller and the Country Gentlemen captured the ears and hearts of a new generation that had never listened to bluegrass before.

"The Country Gentlemen," Washington Post critic Richard Harrington wrote in 1996, "probably made more bluegrass converts in the '60s than Bill Monroe himself."

With Mr. Waller's resonant baritone voice blending with the haunting tenor of John Duffey, the Country Gentlemen expanded the musical language of bluegrass by introducing elements of folk music, country and jazz to its blues and gospel roots. Along with other members of the group, Mr. Waller was admitted to the International Bluegrass Music Association's Hall of Honor in 1996. He was named contemporary bluegrass male vocalist of the year 10 times.

"He had one of the great voices in any kind of music," said Len Holsclaw, who managed the Country Gentlemen from 1971 to 1998. "It stayed with him until the day he died."

As other early members of the group -- Duffey, banjo star Eddie Adcock, bassist Tom Gray -- departed, Mr. Waller carried on the flame as the sole original member of the Country Gentlemen, leading the group until his death.

His final local performances were in late July at the Birchmere in Alexandria. In his review, Washington Post critic Mike Joyce praised Mr. Waller's "unmistakable voice, still warmly resonant after all these years."

Mr. Waller recorded more than 50 albums with the Country Gentlemen, including "Songs of the American Spirit," to be released next week. An article in Bluegrass Unlimited magazine in 2002 described the Gentlemen as "one of the most popular, influential and important bluegrass bands to ever grace a stage or record a song."

Mr. Waller was born in Joinerville, Tex., and moved with his family to Lake Charles, La., when he was 2 years old. In 1945, when he was 10, he followed his mother to Washington, where she ran a boardinghouse. Inspired by country singer Hank Snow, he had his first paying job as a musician when he was 13.

After quitting school in the eighth grade, he worked at a gas station and a body shop while playing music at night. In 1955, he returned to Louisiana as a guitarist with Buzz Busby's Bayou Boys, a bluegrass band that performed on the Louisiana Hayride radio show. As other Hayride performers, such as George Jones, Johnny Cash and Elvis Presley, found fame, Mr. Waller and Busby grew discouraged and decided to try their luck in Washington.

After Busby was injured in a car wreck, Mr. Waller hurriedly put together a group to keep from canceling a performance. The Country Gentlemen made their debut July 4, 1957, at the Admiral Grill in Baileys Crossroads with Mr. Waller on guitar, Duffey on mandolin, Bill Emerson on banjo and Larry Leahy on bass.

The next year, when Adcock, who had been working with Monroe, took over the banjo chair, the band found its new sound. Besides the traditional music of hardscrabble Appalachia, they also did songs by the likes of Bob Dylan, Simon and Garfunkel and Willie Nelson, but in their own acoustic, hard-charging manner.

"The thing we had going for us was we didn't care to sound like the rest," Adcock said in a telephone interview. "We mixed in a few older country songs and folk songs, we did some jazz and movie themes."

The Gentlemen played 12 years at the Shamrock Inn on M Street in Georgetown, touring on weekends. They appeared at Carnegie Hall and at festivals and colleges across the country. Their 1965 album, "Bringing Mary Home," hit the country charts.

In 1969, Duffey left the band, followed a year later by Adcock. But Mr. Waller persevered with new musicians and last year toured with his son, Randy Waller.

His new album is, in the opinion of Adcock, "the best thing he's done in years. His voice is wonderful on all of it."

Mr. Waller's first marriage, to Mona Waller, ended in divorce. His second wife, Kathy Waller, died in the 1960s.

Survivors include his wife of 25 years, Sachiko Waller of Gordonsville; a son from an early relationship, Randy Waller of Falls Church; a daughter from his first marriage, Dori Lane of Cape Coral, Fla.; a son from his second marriage, Danny Graves of Avon, Colo.; and a daughter from his third marriage, Mina Waller of Gallatin, Tenn.; five grandchildren; and two great-grandchildren.

Of the hundreds of songs Mr. Waller performed, his favorite was a traditional bluegrass number called "Letter to Tom." Symbolic of a musician's lonely, memory-filled life, it concludes with these words:

But when our time shall come, dear Tom

And we are called to go

I hope they'll lay us where we played

Just fifteen years ago.

Coming out next week is a new album by Charlie Waller, third from left, and the Country Gentlemen -- Randy Waller, left, Greg Corbett and Darin Aldridge.