Tønnesen is recognised as one of Norway’s leading violinists and concertmasters, and for several decades he has been a central figure in Norwegian musical life. He made his debut in Oslo in 1972, continued his studies in Norway and in Bern, and has since built an extensive international career. For many years, he served both as concertmaster and artistic director of the Norwegian Chamber Orchestra, while also holding the position of principal concertmaster with the Oslo Philharmonic.
Throughout his career, he has collaborated with some of the world’s foremost musicians, including Mstislav Rostropovich, Maurice André and James Galway, and has performed on stages around the world. At the same time, he has been an important communicator of music in Norway – both within the classical repertoire and in encounters with other genres.