The official start of the swing era would begin over ten years after Louis Armstrong joined Henderson's band, and almost a full decade after the birth of the Lindy Hop, the first swing dance.
On the recommendation of Jack Hammond, bandleader Benny Goodman purchased several hot jump tune arrangements from bandleader Fletcher Henderson. Up to this point, hot tunes were mostly only played publicly by African-American bands such as Henderson's band, while sweet tunes were often played publicly by jewish and white bands such as Goodman's band. This was true despite the fact that many sweet bands actually preferred to play the hot tunes. When Goodman's band began performing Henderson's hot tunes, the response was mixed.
In 1935, Goodman's band was scheduled to perform at the Palomar Ballroom in Los Angelas, California. This required the band to travel from the East coast to the West, making performances at stops on the way. At each stop, the hot tunes they tried playing were received poorly.
On August 21st, 1935, they arrived at the Palomar Ballroom and opened the performance with the only songs that were positively received by the audiences during the trip West — the sweet tunes. The response from the audience was to sit and stare without much enthusiasm. At this point, convinced that their careers were over, Goodman signaled to the band to play a hot tune. Goodman felt that if this was going to be the band's final performance ever, then the band would have to die playing the kind of songs the band enjoyed performing.
The audience enthusiasticlly erupted. Unknown to Goodman, these were the songs that the audience had been waiting to hear. The audience had heard the East coast radio broadcasts of Goodman's band performing the hot tunes and it was for those songs that the audience had been excited to hear that he was going to be performing locally at the Palomar Ballroom.
Soon after the Palomar Ballroom performance, and the media's commentary on the performance, Benny Goodman's band has taken the top 3 spots on the record charts in California. Benny Goodman was now being billed as the "King of Swing" and the Palomar Ballroom performance of August 21st, 1935 would later mark the official start of the Swing Era.
Swing jazz soon came to dominate the American social world. Every country club, night club, ballroom, radio, and the background music of the movies was filled with swing jazz. People foxtrotted to the sweet swing jazz tunes, and people were Lindy Hopping to the hot swing jazz tunes.
During World War 2, swing remained popular, and both large and small ensembles toured with the USO to entertain at Army and Navy camps. The USO brought a piece of home and normality to the soldiers and sailors dealing with the stress of war, away from home and family.