On June 26, 1950, he recorded the American version of the song (English lyrics by Jerry Seelen) in New York City with Sy Oliver and his Orchestra. When it was released, the disc was a worldwide success and the song was then performed by the greatest international singers. In the 1960s, he toured Ghana and Nigeria.
After finishing his contract with Decca Records, he became a freelance artist and recorded for other labels. He continued an intense international touring schedule, but in 1959 he suffered a heart attack in Italy and had to rest.
In 1964, after over two years without setting foot in a studio, he recorded his biggest-selling record, "Hello, Dolly!", a song by Jerry Herman, originally sung by Carol Channing. Armstrong's version remained on the Hot 100 for 22 weeks, longer than any other record produced that year, and went to No. 1 making him, at 62 years, 9 months and 5 days, the oldest person ever to accomplish that feat. In the process, he dislodged the Beatles from the No. 1 position they had occupied for 14 consecutive weeks with three different songs.