The emerging literature concerning sustainable careers posits that career development is an adaptive and dynamic process of creating person–career fit, in pursuit of a career that is happy, healthy, and productive. Our goal is to advance this literature by delving deeper into the intrapersonal processes involved in constructing career sustainability—which involves meeting one’s needs in the present without sacrificing one’s needs in the future—and clarifying the role of time in this process. We articulate a fundamentally subjective, intrapersonal process of enacting career sustainability that draws upon career construction theory, prospective and adaptive sensemaking, conservation of resources theory, and career adaptability to articulate how individuals reflect, frame, envision, re-frame, and ultimately, adapt to effect and maintain their career sustainability over time. This expansion brings added conceptual depth to earlier sustainable careers models by situating the career firmly within the agency of the career actor and articulating how this process unfolds with specific recognition of the past, present, and future. Educators, career counselors, HR representatives, and community organizations are called upon to promote and support career sustainability and support individuals through this dynamic and adaptive process.