The rejection of “Old Town Road” by the country establishment, in Mr. Hughes’s view, echoed a time when country radio stations ignored Ray Charles’s groundbreaking 1962 album, “Modern Sounds in Country and Western Music.”

Lil Nas X, whose real name is Montero Hill, said he wrote “Old Town Road” last fall, after staying with his sister while avoiding his parents as a college dropout. When his sister finally sent him on his way, he imagined his future.

“I felt like a loner cowboy,” he said. “I wanted to take my horse to the Old Town Road and run away. The horse is like a car. The Old Town Road, it’s like a path to success. In the first verse, I pack up, ready to go.”

He posted the song online in December along with an observation: “country music is evolving.” It soon became a sensation on TikTok, an app that allows users to make and share short music videos. Young people made video shorts of themselves dressing up in cowboy gear, using the song as a soundtrack. By March, Lil Nas X had nailed down the deal with Columbia.

In an interview on Friday, he sidestepped questions about being dropped from the country chart. “I’m still in Billboard — this is amazing,” he said. This week, the song climbed 17 spots, to No. 15, on Billboard’s Hot 100, which measures the popularity of pop songs.

The blending of country music and black American forms is certainly nothing new. The white guitarist Jimmie Rodgers, whom many consider the father of country music, built the genre on a foundation of the blues in the 1920s. Ray Charles’s innovations in the early 1960s paved the way for the Nashville success of another black artist, Charley Pride. More recently, Darius Rucker, of the rock band Hootie and the Blowfish, had a No. 1 country hit with “Don’t Think I Don’t Think About It.”

Last year, Jimmie Allen, a black performer from Delaware, made Billboard’s country top 10 with his debut single, “Best Shot.” Another African-American singer, Kane Brown, had two No. 1 hits on Billboard’s country chart, one in 2017 and one in 2018.