Sid Mark, a longtime disc jockey in Philadelphia who made Frank Sinatra’s songs the center of his wide-reaching musical universe for more than six decades, died on April 18 in Bryn Mawr, Pa. He was 88.

He hosted three shows on various Philadelphia radio stations: “Friday With Frank,” “Sunday With Sinatra,” and the syndicated “The Sounds of Sinatra,” which has run for 43 years and at its height was heard on 100 stations. He also hosted a fourth, “Saturday With Sinatra,” on stations in New York.

His admiration for Sinatra’s music swelled when he listened to his records on the radio at night in 1953 in the Army barracks at Camp Polk in Louisiana. “Somehow his voice got to me, and I realized he knew exactly what he was singing about,” he said. “If he was singing about lonely, he knew what lonely was. If he was singing about love, he knew what love was about.”

Mr. Mark hosted “Friday With Frank” for 54 years, “Saturday With Sinatra” for about 17, and “Sunday With Sinatra” for more than 40. “The Sounds of Sinatra” will remain on the air and present archival shows, said his son Brian Mark, the executive producer.