The high-school band Royal Swingers was founded in Uppsala in 1940 by the pianist Gösta Eriksson, who acted as a leader, Åke Hasselgård, guitarist Kurt Wärngren and drummer Bertil Fryhlmark. Sometimes, trumpet player Bror Hansson joined the quartet. They played for student dances in the university and did a few gigs in Stockholm. It was an amateur band and we can assume that the members, at least now and then, spent some time attending high school.

The breakthrough came when the group won a band contest in Stockholm, December 1941, arranged by the jazz magazine OJ. This led to a recording session for Brunswick in the summer of 1942, resulting in four sides (and a surviving alternate take) with the band, labeled as Gösta Eriksson's Quintet, now with the addition of Simon Brehm on bass.

An earlier session was planned for Sonora in January, but aparently never materialized. The band continued to play gigs while several members continued their studies at the Uppsala university. In January 1944, OJ reports that the band had broken up, since Hasselgård had started a group of his own with pianist Per-Erik Sparrings instead of Eriksson. Private recordings from 1944–45 still include Eriksson, according to the discographical details given by Dragon. Sparrings does not appear until August 1946 on a private recording from the north of Sweden, indicating that the band toured the country.

In 1945, having served his time in the army, Åke Hasselgård took his first professional job with the Arthur Österwall quintet that lasted almost a year, touring the "Folk Parks" in the summer and working at Nalen during the winter season. Thore Swanerud played the piano and wrote several arrangements – collaborating with Hasselgård who still could not read or write music.

Swanerud was not only an exceptional pianist, he also had a total "photographical" music memory. He remembered every note that he had heared in his life and shocked Benny Carter in the 1980s with the question: "Do you remember the solo you played in the Stockholm Concert Hall in 1936?" – and then he played it on the piano!

Thore always remembered and mourned Hasselgård and once showed me, when I sat in with his trio, how he fooled Hasselgård:

"Åke had heard that Goodman never played a second line and decided that he too would not, but on this arrangement I fooled him. Listen, I played this part and Åke played this, actually a second line." I wish I remembered what tune it was.

The Royal Swingers reappeared in 1946, now with Thore Swanerud on the piano (sometimes also reluctantly playing the vibraphone) on six sides recorded by the Telefunken label Musica. Often the band was featured as Simon Brehm’s band. In addition to the discs,

The group’s last recording featured Tyree Glenn on trombone and vibraphone. One month later, in the end of April 1947, four of the band’s members were voted into the 1947 all star favorite band!

Hasselgård went back to Uppsala in order to finish his studies.