The (Nashville) Tennessean confirmed the Sunday morning death of Grant, an original member of Johnny Cash's Tennessee Two band and longtime Cash family friend.
"I was thinking yesterday that there would be no me without Marshall," Cash's daughter, singer-songwriter Rosanne Cash, told the newspaper. "Had Dad not had Marshall, he wouldn't have had the 'Johnny Cash Sound,' and he wouldn't have become all that he was, in his fullness. And I wouldn't have become a songwriter or a musician. There's a whole lineage that wouldn't have happened."
Grant also managed The Statler Brothers until their 2004 retirement.
The musician and his wife, Etta, drove from their Hernando, Miss., home to Jonesboro, last week to take part in the Johnny Cash Festival, but he fell ill after visiting with members of the cash family Wednesday, the Tennessean reported. He had been scheduled to perform at the festival Aug. 4.