McCoy, who got her start working five days a week as a radio host at the age of 12, beat the previous record by more than three years, Guinness said.
"Growing up my dream was to get into the entertainment business. I started out singing at talent shows and I was asked to audition for a radio show," she told Guinness. "They liked what they heard and I started working at KMCO Radio on April 20, 1951, doing a 15-minute singing program."
The now-85-year-old still hosts the two-hour Country Classics show six days a week on KVST K-Star Country in Huntsville.
McCoy also had a music career in addition to her DJ duties, and once shared the stage with Elvis Presley when the singer and his band joined her for a few songs in 1955.