Sune "Sumpen" Borg was born in Stockholm on September 3, 1931. People have always called him by his nickname, "Sumpen". At the age of 13 he learned how to play the piano by listening to his 78 rpm records. Sune's first record was "King Porter Stomp" played by Harry James. After the WWII he purchased the recording of "Pinetop" Smith's "Pinetop's Boogie-Woogie", which he used to play all day long.

Influenced by Sidney Bechet's version of the "Maple Leaf Rag" he used to play it very fast. After hearing "Jelly Roll" Morton's recordings he realized that ragtime shouldn't be played *that* fast. In the late 40's "Sumpen" was known in Stockholm as a very talanted pianist. People called him "The Master", "The One And Only". He played ragtime and boogie woogie like no one else.

In October 1949 he recorded two piano solos, "Original Rags" and "Maple Leaf Rag" for the Gazell recording company (Gazell 3001). He used to play with "Olle Sundhs Dixieland Band" at the popular dance palace "Nalen" and at the "Gazell Club". In the 50's they toured around the country and played in many people's (amusement) parks. Their music was often played on the radio.

"Sumpen" never played ragtime "straight", he used to "swing" the tunes in a jazzy manner. In 1966 he composed his only notated rag, "Ylva Rag", named after his daughter and dedicated to her.

Between 1968 and 1991 he worked as a director of the National Board of Agriculture, first in Stockholm, and then in Jönköping. He moved back to Stockholm in 1996, and lived there until his death on January 20, 2002. Only 8 days before "Sumpen" Borg passed away, he attended the annual meeting of "The Swedish Bunk Johnson Society" in Stockholm, where four of his Swedish ragtime colleagues gave a 90 minutes performance.