How organizations legitimate their actions under conditions of institutional change is a central yet little understood question. To address this gap, this paper investigates how incumbent firms legitimate investments in both novel and conventional technologies during periods of institutional and technological transition. We examine the rhetorical strategies that energy incumbents employ to gain legitimacy for their investments in renewable (legitimacy-gaining or novel) and non-renewable (legitimacy-losing or conventional) technologies. Employing a mixed-method content analysis of 483 press releases on strategic energy investments, published by the world’s largest energy firms during the time period 2010 to 2015, we find that incumbents utilize two different types of hybrid rhetoric to justify their investments. For investments in non-renewables, incumbents use pragmatic blending, appropriating the clean rhetoric traditionally associated with challenger technologies and combining it with justifications highlighting performance-oriented outcomes. The rhetoric used for investments in renewables involves visionary blending, combining rhetoric related to corporate strategy with sustainability rhetoric. We furthermore argue that these hybrid rhetorical strategies are observed when the legitimacy trajectories of two technologies intersect. Our study contributes to the research on rhetorical institutionalism, incumbents’ role during institutional change, and technology legitimacy.