NASHVILLE, Tenn. – Eddy Arnold, whose mellow baritone made him one of country music's most successful singers, died Thursday morning, days short of his 90th birthday.

FILE 2002/The Associated Press

Mr. Arnold died at a care facility near Nashville, said Don Cusic, a professor at Belmont University and author of Eddy Arnold: I'll Hold You in My Heart. His wife of 66 years, Sally, had died in March, and in the same month, Mr. Arnold fell outside his home and injured his hip.

Mr. Arnold's vocals on songs such as 1965's "Make the World Go Away," one of his No. 1 country hits and a top-10 hit on the pop charts, made him one of the most successful country singers in history.

Folksy yet sophisticated, he became a pioneer of the Nashville Sound, also called countrypolitan – a mixture of country and pop styles.

"I sing a little country, I sing a little pop, and I sing a little folk, and it all goes together," he said in 1970.

He was elected to the Country Music Hall of Fame in 1966. In 1967, he was the first person to receive the entertainer of the year award from the Country Music Association.

Top Country Singles 1944-1993 by Joel Whitburn ranked Mr. Arnold the No. 1 country singer in terms of overall success on the Billboard country charts. It lists his first No. 1 hit as "What Is Life Without Love," 1947, and for the following year ranks his "Bouquet of Roses" as the biggest country hit of that year.

Most of his hits were done in association with famed guitarist Chet Atkins, the producer on most of the recording sessions.

He revitalized his career in the 1960s by adding strings, a controversial move for a country artist back then. "I got to thinking, if I just took the same kind of songs I'd been singing and added violins to them, I'd have a new sound," he told The Associated Press in 2002. "They cussed me, but the disc jockeys grabbed it. ... The artists began to say, 'Aww, he's left us.' Then within a year, they were doing it!"

Among his recent albums were 2002's Looking Back and 2005's After All These Years.

Mr. Arnold invested wisely, especially in real estate in the Nashville area, and was regarded as one of the wealthiest men in country music. He once had this advice for young singers: "Get a good lawyer, a good accountant and be on time."

Friends said his wife helped handle his business dealings and was the inspiration for many of his love songs. "What hurts me more than anything else is that he died of a broken heart," said Grand Ole Opry star Jim Ed Brown, a friend.

Mr. Arnold was born May 15, 1918, on a farm near Henderson, Tenn., as the son of a sharecropper. He sang on radio stations before becoming nationally known.

He lived in Brentwood, a Nashville suburb. Survivors include a son, Richard Edward Arnold Jr., and a daughter, Jo Ann Pollard, both of Brentwood.

The Associated Press