What promotes action competence for sustainability? This question is phenomenologically explored through researching in depth the life stories of three Swedish young adults who for several years have limited their own ecological footprints, led environmental initiatives of activist character, engaged in ecosystem protection, and participated in advanced non-activism in the public sphere. Narrative analyses of their life stories have resulted in six common themes: emotions creating a desire to change conditions; a core of values and contrasting perspectives; action permeation; feeling confident and competent with what one can contribute; trust and faith from and in adults; and outsidership and belongingness. (Contains 1 note.)