When Thomas Edison “Brownie” Ford makes his Jazz Fest appearance on Saturday, May 1, he’ll have time to turn just a few pages of his encyclopedic song repertoire. But the 89-year-old gentleman cowboy singer says that’ll be enough.

“There was a time I was accredited with doing about a thousand songs,” says Ford, speaking by phone from his home in Hebert, Louisiana. “Now, I don’t know if I could do that many songs anymore. But I can remember enough to put on a show.”

Ford’s rich vein of ...