Mørk was born in Bergen, Norway, on April 25, 1961. His father, John Fritjof Mørk, was a cellist, and his mother, Turid Otterbech, was a pianist. She began giving him piano lessons at age seven, and he also studied the violin. Finally, he settled on the cello and began taking lessons with his father and then with Frans Helmerson at the Edsberg Music Institute. He gravitated toward the playing of Mstislav Rostropovich and began studying with cellist Natalia Shakhovskaya. Mørk reached the finals of the 1982 Tchaikovsky Competition in Moscow, becoming the first Scandinavian musician to do so since 1966, and he took second prizes at the Naumburg Competition in New York and the Cassado Cello Competition in Florence. In 1988, he made his recording debut on the Simax label, joining pianist Juhani Lagerspetz on a recording of Brahms' two sonatas for cello and piano.
Mørk made several more recordings for Simax through the early '90s. He toured the U.S. with the Oslo Philharmonic Orchestra under conductor Mariss Jansons in 1994 and went on to appear as a soloist with many of the world's major orchestras. Mørk's repertory encompasses the standard cello concertos as well as new works by Pavel Haas, Krzysztof Penderecki, and Einojuhani Rautavaara, among others. An enthusiastic chamber music player, Mørk appears frequently in festivals around the world and founded an event of his own, the International Chamber Music Festival in Stavanger, directing it for 13 years. Mørk contracted encephalitis and paralysis from a tick bite he suffered while on tour in the U.S. in 2006; he was forced to take 18 months off from performing, but he recovered. Mørk has recorded prolifically for Virgin Classics, Ondine, and Chandos, among other labels; by 2022, when he moved to Alpha for a recording of cello sonatas by Bridge, Britten, and Debussy, his catalog numbered well over 40 releases. ~ James Manheim, Rovi