Magnus Murphy Joelson is a Norwegian trombone player, arranger, composer and band leader from Sandefjord in Norway. He started playing in his local school band and later the city's big band, starting his interest for large musical ensembles. He went on to study jazz at Toneheim Folkehøgskole and getting his bachelor's degree in jazz trombone at the University of Stavanger. Later he obtained his master's degree in jazz performing and composition at the Norwegian Academy of Music in Oslo, where he also studied conducting and contemporary composition.

Joelson is an active freelance musician in Oslo, performing and conducting as well as arranging and composing music, and more. He is active in projects such as OJKOS (Orkesteret for Jazzkomponister i Oslo), BenReddik, Vestfold Jazzensemble, his own Magnus Murphy Bigband and more. In 2019 he released his debut album "Skandinavia" with his octet.

Joelson has worked as an arranger for among many the Norwegian Radio Orchestra, the Norwegian Wind Ensemble and Bjergsted Jazz Ensemble. He has written comissions for Ojkos, Oslo Jazz Ensemble, Vocal Art Frankfurt Rhein Main, Toneheim Folkehøgskole, Det Nye Norske Storband and more. He is also the musical leader and conductor for Birkelunden Bigband in Oslo.