In the late 1950s, while stationed in Germany with the U.S. Army, Presley heard Martin's recording. According to The New York Times, quoting from the 1986 book Behind The Hits, "he told the idea to his music publisher, Freddy Bienstock, who was visiting him in Germany... Mr. Bienstock, who many times found songwriters for Presley, returned to his New York office, where he found songwriters, Mr. [Aaron] Schroeder and Wally Gold, the only people in that day. The two wrote lyrics in half an hour. Selling more than 20 million records, the song became number one in countries all around and was Presley's best selling single ever... a song [they] finished in 20 minutes to a half hour was the biggest song of [their] career."
In 1960, "It's Now or Never" was a number-one record in the U.S., spending five weeks at number one and the UK, where it spent eight weeks at the top in 1960 and an additional week at number one in 2005 as a re-issue, and numerous other countries, selling in excess of 25 million copies worldwide, Elvis Presley's biggest international single ever. Its British release was delayed for some time because of rights issues, allowing the song to build up massive advance orders and to enter the UK Singles Chart at number one, a very rare occurrence at the time. "It's Now or Never" peaked at number seven on the R&B charts.
Barry White credited this song as his inspiration for changing his life and becoming a singer following his release from prison.
A live version featuring "'O Sole mio" is available on the 1977 live album Elvis in Concert. "'O Sole mio" is sung by tenor Sherrill Nielson.
In early 2005, the song was re-released along with the other Presley singles in the UK, and again reached number one on the UK Singles Chart for the week of 5 February 2005. The re-release held the record for the lowest selling number-one single in UK chart history until Orson's "No Tomorrow" in 2006. The song also appears in the TV mini-series Elvis.
At the 20th anniversary concert of the Suntory Hall in Japan in 2006, Italian tenors Vincenzo La Scola and Giuseppe Sabbatini and American tenor Neil Shicoff sang a bilingual version of the song together. For their respective solo parts, the two Italians sang the original Neapolitan lyrics, while Shicoff sang two segments of "It's now or never"; and all three joined together for the final chorus with the Neapolitan lyrics.