Stalheim is internationally recognized as an accordion soloist and has performed on numerous CDs and with several international orchestras. He has performed at many festivals and concert-series. He founded the first accordion festival in Norway: Nordic Accordion Symposium. Stalheim has cooperated with several composers and performed works by Unsuk Chin, Georg Friedrich Haas, Steen Pade, Ib Nørholm, Ketil Hvoslef, a.o.
Stalheim is also a composer with a broad range of works with recent performances by orchestra, opera and ballets in San Francisco, St. Petersburg, Oslo and Paris.