There is a widely accepted sentiment that a large and growing segment of the developed world experiences life and work in a more dynamic and less predictable way than ever before. Many people, across a wide spectrum of age cohorts, will engage in frequent transitions throughout their lifetimes. Some will relocate multiple times and will traverse numerous peaks and valleys of change during those career and life transitions. Streams of research have been dedicated to the negative consequence of dealing with these disruptions as compared to a stable and settled existence. Large bodies of research and commentary have been produced on how to manage the difficult process and negative consequence of accelerating change. In contrast, my research offers empirical evidence that such transitions can result in positive consequences for one's well-being. It is a study of how thriving can become a "normal" outcome of experiencing change and how we might revise the lexicon and expectations of engaging in transitions. I conducted three studies on the ontological experience of thriving in transition. Using an exploratory, sequential and embedded mixed-methods approach, I identified social, cognitive, psychological and behavioral factors that contribute to thriving in transition. As a result of the current study, I elucidate an abstract system that contains four representative ontologies of change forming a skeletal framework for a descriptive model on thriving and surviving in uncertain times. The 4-quadrant model is divided by the degree of change together with an individual's ontological organizing principle relating to the phenomenon of change; stability is the norm or change is the norm. This abstract model has predictive value in identification of cognitive, social and behavioral resources at a time of change. At any given point in one's life, a transition can be interpreted in terms of the magnitude of change (how big or how little the change) and the individual's ontological experience of change (whether it disrupts an equilibrium or continues to be part and parcel of an evolving, cyclical and emergent way of life). Contingent upon these two dimensions, one can use this framework to ignite self-discovery and mobilize resources to design a response and hypothesize a desired outcome. The four quadrants represent different ways to live. Individuals may find themselves at various junctions of these quadrants over a lifespan. These four quadrants provide "requisite variety" to navigate individual ontology as they move into and out of fluid spaces we often call instability during a time of transition. Thriving in transition is an iterative, non-linear, and a generative process that produce knowledge, agility and other beneficial resources. It is fueled by positivity, as one negotiates and develops dynamic self-knowledge in the context of new stimuli. Two new constructs were developed to empirically operationalize findings from my initial qualitative study: Transformation Quotient (TQ) and Thriving Transition (TT). TQ measures an individual's receptivity to change as demonstrated by the willingness and ability to embrace transition as an ongoing activity as well as fully engaging in the metamorphic potential inherent in transitions. TT measures an individual's psychosocial "prosperity" that includes several universal human psychological needs such as competence, autonomy, relatedness and self-acceptance, as well as positive social relationships, the desire to learn, and vitality for life. The pop-culture notion of carpe diem, YOLO (you only live once), or FOMO (fear of missing out) captures the spirit of TT combined with TQ. The first study utilized a grounded theory approach. It was a qualitative data collection and analysis on international mobile professionals that informed the conceptualization of the "Thriving in Transition" model. Subsequent quantitative analysis in Study II, and embedded mixed-methods analysis in Study III empirically tested social, cognitive and behavioral factors influencing well-being at a time of change as part of the "Thriving in Transition" model. Three key integrated findings from this body of work are: 1) the importance of the construct Improvisation Behavior as both a cognitive and a behavioral resource; 2) the validation of the new construct TQ across two studies and the positive significant relationships found to TT in Study III; 3) the interaction between Improvisation, Self-knowledge and TQ that creates the foundation for expanding the current 4-quadrant abstract model as a useful paradigm to describe and predict thriving in transition. Other findings include social, cognitive and emotional factors at a time change. Perceived social support and positive cognitive appraisals are positively related to Flourishing in Study II; emotional response to uncertainty is negatively related to TT in Study III for subjects whose ontology of change is one where stability is the norm. Across studies, Improvisation behavior turned out to be an extremely powerful concept in thriving in transition. In Study II, a quantitative study, the independent variable, Improvisation behavior across magnitude of change, has a positive and significant relationship with TQ. Improvisation also has a direct, positive and significant relationship to Flourishing (a reflective construct measuring an individual's psychosocial prosperity) for various magnitudes of change. In Study III, Improvisation is only relevant to individuals who report a high degree of change, and ontologically view change as the norm. For individuals in this quadrant, Improvisation has a strong, significant and positive relationship with TT. These findings are backed by research on how environmental turbulence tends to have a positive influence on catalyzing the improvisation process. "Practicing improvisation" contributes to thriving in transition due to positive knowledge production, flexibility improvement and positive affective outcomes. Transformation Quotient (TQ) partially mediates the relationship between Improvisation and Flourishing for participants without global relocations in Study II. In Study III, TQ is relevant to all groups except one--positive, strong and significant effect for individuals who experience various magnitude of change and who have the view that change is the norm. However, a negative, strong and significant effect is observed between TQ and TT for those who experience high degree of change and view stability as the norm. TQ as a mediator in Study II and an independent variable in Study III provide empirical evidence that TQ is a relevant construct in the conceptual framework of thriving in transition. TQ is defined in this research as an aptitude for change, potentially developed to be a navigational competence in the quest for eudaimonic well-being in uncertain times. Also, in Study III, self-knowledge is hypothesized to be a cognitive resource and an important factor contributing to thriving in transition. However, no significant relationship was observed between Self-knowledge and TT for individuals who experience high degree of change and ontologically organize change as the norm. Indicated by qualitative data from Study III, these individuals deploy a combination of intuition, creativity and bricolage to convert self-knowledge into action, they benefit from deploying Improvisation behavior both as a behavioral and a cognitive resource. Improvisation is a behavioral resource; it is when individuals take action as the situation unfolds while drawing upon available material, cognitive, affective and social resources in problem solving. It is also a cognitive resource; the act of Improvisation offers individual an opportunity to re-interpret new stimuli. Sense-making, dialectical cycling and narrative identity are the three key mechanisms that drive the difference between thriving transitions versus merely surviving transitions. The experience of transition rests with the individual's ontological experience of change and the intervention sequence deployed in response to various degrees of change. My dissertation contributes to positive organizational scholarship, antecedents and consequences of transitional experiences through a 4-quadrant system of understanding thriving in transition. This framework provides the initial structure to help individuals navigate toward eudaimonic well-being and fulfillment during uncertain times.