Strønen attended the Jazz Program at Trondheim Musikkonservatorium (1995–99). He has participated in the following bands; Pohlitz (solo project), Humcrush with Ståle Storløkken and occasionally Sidsel Endresen, Food with Iain Ballamy and sometimes Christian Fennesz and the Swedish-Norwegian band Parish with Bobo Stenson, Mats Eilertsen trio (with Harmen Fraanje) Meadow with the British pianist John Taylor and Tore Brunborg. Furthermore, he plays with Maria Kannegaard Trio, Reflections in Cosmo (feat. Ståle Storløkken, Kjetil Møster, Hans Magnus "Snah" Ryan), Time Is A Blind Guide (feat. Ayumi Tanaka, Ole Morten Vågan, Leo Svensson Sander and Håkon Aase), Trinity and Turanga. He has also made several commissioned works, and produced and arranged works for a variety of artists. Strønen is also an associate professor at Norges Musikkhøgskole.

Strønen is recording for the renowned German label ECM and also for Rune Grammofon. As a composer, Strønen has contributed to the release of over seventy recordings as well as several commissioned works for festivals (including the Bath and Cheltenham Jazz Festival and Ultima Contemporary Music Festival) and radio (DR, BBC, Deutsche Rundfunk, NRK, BBC, Swedish Radio, and others)