In 1921, he became the leader of the orchestra known as the Palads Cinema of Copenhagen, the largest theater orchestra in the city. He wrote his most famous work, the tango Jalousie (Jealousy), as part of the accompaniment of a silent film.
This tune swept the entire world. It is one of the five best-known popular tunes in history. In the 1970s, based on reports of its royalties, it was estimated that since it was written, it had been played by some professional musician somewhere in the world every minute of every day, and was played more often than any other song until Lennon and McCartney's Yesterday pushed it to number two. It has frequently been parodied, but it continues to have immense popular appeal, particularly as the tango entered a period of revival after 1985.
Gade's full-time performing career ended in 1931 when the Palads Cinema disbanded its orchestra as talking pictures replaced silents. Gade moved back to rural Denmark, living very comfortably on the substantial royalties earned by Jalousie and other pieces, writing more ambitious orchestral scores.