User Experience (UX) is characterized by its temporal dimension, dynamic nature, and variability. Although descriptive models about the temporal dimension and related aspects exist, an understanding of the design possibilities and a design approach that ensures the design of the temporal dimension promoting a positive UX and well-being are still lacking. This paper addresses this research gap and builds on Zimbardo and Boyd’s Time Perspective Theory (TPT). TPT presents five time perspectives (TPs)—Past-Negative, Past-Positive, Present-Fatalistic, Present-Hedonistic, and Future—to reveal that people have individual attitudes toward time that influence their thoughts, actions, and feelings. Studies conclude that a balance between the positive TPs (Past-Positive, Present-Hedonistic, and Future), i.e., temporal harmony, contributes to long-term well-being. We present our design framework and approach “designing for temporal harmony,” which incorporates the theory into the practice to highlight the temporal design possibilities and to offer guidance for designers. We applied the design framework and approach to a case study, developed an app concept, and evaluated it with users. The results demonstrate that it is possible to systematically develop temporal UX concepts that evoke positive anticipations, experiences, and retrospections, and that these promote a positive UX as well as contribute to users’ long-term well-being.