Focusing on a Vygotskian theory of cultural historical psychology, this dissertation features a narrative analysis to examine the role of subjectivity and the generative potential and agency manifested in Non Native English Speaking Teachers' (NNESTs) successful development of L2 (English) fluency. My research creates another view of a Vygotskian theory by means of the imagination. Building on a cultural-historical approach, I conducted a qualitative analysis of how these teachers' pathway to fluency evolved from their Imagined Destinations. This term is defined as a goal or objective in the mind of the learner that mediates, and is mediated by, his or her lived experiences. The concept I coin as Imagined Destinations surfaced in my three initial pilot cases and took shape while working with NNES Panamánian teachers, from the analysis of online survey data with 27 of these experienced teachers, and detailed case study analyses of the language learning of eight of these teachers. These data revealed how participants dynamically create and recreate their environments through agentive roles that support the transformation of their environments to advance their goals. These transformations have implications for how subjectivity, agency, and acquisition of the target language intertwine throughout the participants' lived experiences or pathways to learning, thus providing an additional way to look at subjects and subjectivities within a Vygotskian theoretical frame. The findings also indicate that teachers' language trajectories are continuous, emergent, and the result of taking on very deliberate ecological roles in their bilingual success despite recurring salient and limiting circumstances. These findings about the centrality of Imagined Destinations in learning "smudges" the perception that societal power outweighs the dynamic and agentive roles of individuals as active molders of their lives. Finally, this dissertation also seeks to enrich scholarship by demonstrating how NNESTs use their bilingual identities built from their trajectories to bilingualism as ways to influence and inspire their own students' second language learning.