<p>This article explores the relationship between subjective energy and a tendency toward extremism, expressed through setting of demanding and ambitious goals, fierce goal commitment, and pronounced focus on one’s dominant purpose at the expense of other objectives. We hypothesized that these features of extremism require substantial energy investments, hence individuals who feel highly (versus less) energetic would be particularly likely to exhibit them in their cognitions and behavior. We also postulated that the relation between feeling energized and tendency toward extremism would be mediated by higher expectancy of goal attainment on part of the more energetic individuals. We tested these hypotheses in three studies, two correlational and one experimental. In Study 1 (<i>N</i> = 621), we found a positive relationship between subjective energy and the likelihood of setting extreme goals. Mediation via optimism (i.e., generalized expectancy of positive outcomes) was not supported. In Study 2 (<i>N</i> = 267), we found a positive relation between subjective energy levels and extreme commitment to self-chosen personal goals. This relation was mediated by state optimism as well as by specific expectancy of goal attainment. Finally, in Study 3 (<i>N</i> = 175), we manipulated energization by having participants listen to either energizing or calming music and measured their commitment to an important personal goal. As anticipated, participants in the energizing (vs. control) condition showed greater extreme commitment to their personal goals, which effect was mediated by increased situational optimism.</p>