Lasse Andersson is a Swedish musician renowned for his skills on the accordion, double bass, and contrabass. He was born on July 27, 1939, in Björkvattnet, Jämtland. His musical education includes five years of studying double bass at the Academy of Music and obtaining a degree in cello pedagogy from Borgarskolan. Over the years, he has performed both classical and jazz music in numerous orchestras.

Andersson's musical journey began in his hometown, where he first learned to play the accordion. At the age of nine, he enrolled in a correspondence course taught by Andrew Walter. When he was 13, he moved to live with his aunt in Kungsör and took up a job at a factory. The following year, he secured employment in Eskilstuna, where he also worked as a postman at the age of 15. It was during this time at the youth center that he formed his first ensemble, Lasse Andersson's quartet, continuing to play the accordion. He achieved the title of accordion master in 1956 and later transitioned to the double bass after completing his military service. He studied under Professor Knut Gullbrandsson and attended Musikhögskolan, where he was taught by Professor Torvald Fredin.

In the 1970s, he gained further recognition by appearing in a television series alongside notable figures such as Stig Emanuelsson, Bert-Åke Varg, and Sone Banger. Throughout his career, Andersson collaborated with various accordionists, including Art van Damme, Calle Jularbo, Conny Sahm, Erik Frank, and Sone Banger. His versatility allowed him to perform with classical groups such as the Filharmonikerna and the Hovkapellet, though he primarily focused on jazz, particularly with his own quartet.

Andersson's performance credits include touring with Evert Taube, playing in theater orchestras at Dramaten and Stadsteatern, and contributing to over 300 performances of "La cage aux folles" at the Oscars theater in Stockholm. He also shared his knowledge through teaching at Framnäs and KMI.

In 1961, he met his future wife, Gunilla, at Ramundberget, and they married in 1964. Their son, Benny, was born later that same year. The family has lived in various locations, including the inner city of Stockholm and the suburbs of Bredäng, Älvsjö, and Ekerö. They also own a farm with forest land in Andersson's hometown of Jämtland.

His home is equipped with three accordions, a piano, and several basses. Notably, he purchased a piccola bass from Ron Carter, who had borrowed Andersson's double bass for a performance at the Skeppsholmen jazz festival. At the age of 66, he completed his first Vasaloppet ski race.

Currently residing in Tranebergs strand, Bromma, Andersson enjoys time with his family, which includes his wife Gunilla, son Benny, and four grandchildren. He holds the distinction of the longest contract, having spent 16 summers performing with Bosse Larsson on "Allsång på Skansen." Among his most memorable performances are those with Art van Damme, Clark Terry, Nelson Riddle, and Warren Vaché. His extensive network of collaborations features artists such as John Kongshaug, Giovanni Jaconelli, Håkan Elmquist, Bernt Dahlbäck, Thore Skogman, Yngve Sandström, Weine Renliden, Eva Bysing, Bertil Frylmark, Sten Carlberg, Lennart Wärmell, Lill-Arne Söderberg, Ebbe Jularbo, Nils Lundin, Bengt Högberg, and Dick Gyllander. He is also associated with Pyramid Records (13).