While completing his studies, Cortese performed with the Philadelphia Orchestra and the Boston Symphony, and was offered the Principal Viola position in the Teatro alla Scala. In 1986 he became the leader of the viola section of the Gothenburg Symphony orchestra under their music director Neeme Järvi. He made his debut with orchestra in Alice Tully Hall in New York in 1991. Although he has been guest principal viola in over twenty European orchestras, Cortese dedicates an increasing amount of time to solo and chamber music playing.
Cortese has performed extensively in the US, Canada, and the European Union, collaborating with numerous chamber music groups such as the Kandinsky Trio, the Trio Arbós, Quatuor Diotima, and other groups, participating in international music festivals such as Tanglewood, Evian, Banff, Musicades of Lyon, Granada, Grand Teton, and many others. He has performed on numerous occasions with Context, a flexible chamber group of historically informed interpretation in the US. In Spain, he has been a member of the Beethoven Klavierquartett for over twenty years, and the Arts Quartet in Barcelona for more than ten years.
Cortese has recorded works by Elliot Carter, William Bergsma, Alan Hovaness, Vincent Persichetti, and George Rochberg , Shostakovich, Martinu, and works by Otto Luening, Witold Lutoslawski, Rebecca Clarke, Ralph Vaughan Williams, Walter Piston, and Roy Harris, Milhaud, Ernest Bloch, Debussy, etc. for DG, Chandos, ASV, Crystal, Posh Boy Music, and many others, most notably the complete works of Paul Hindemith, in honor of his centenary, with the Philharmonia Orchestra of
London on the ASV label, the only recording of its kind.
Born in Wisconsin to Italian parents, Paul currently lives in Barcelona, Spain, where he is professor of viola and chamber music at the conservatory of the Liceu. He is the administrator of Facebook Violists, the largest group of its kind dedicated to the viola, and has taught masterclasses in Spain, Italy, France, Vietnam, the US, Poland, Latvia, Germany, Estonia, Georgia, Azerbaijan, Cyprus, Moldova, Brazil, Hungary, Mexico, Australia, and Colombia. He currently plays a viola constructed for him by the fine Spanish maker Agustín Clemente of Madrid in the year 2006, a viola by Guillem Gecubi, Barcelona, 2005, and a viola by Daniel Hoffman, New York, 2010. Paul is a Larsen Strings Performing Artist since 2019.