The teaching profession has been increasingly subjected to a managerialist perspective of professionalism. Concurrently, neoliberal strategies redefine the nature of teachers' work, constrain teachers' agency and jeopardise their professional identities. In light of escalating bureaucratic pressures and diminishing professional autonomy, the imperative to explore paths for reinforcing teacher agency becomes paramount. Drawing on an ecological view of agency, the authors conceptualise teacher agency as a dynamic and context-dependent phenomenon. This paper seeks to identify how teachers enact their agency and to scrutinise the enablers and constraints of teacher agency, focusing on the life stories of 102 Portuguese teachers over the past five decades. Through a paradigmatic analysis the authors delve into the interplay of individual experiences, cultural contexts and structural influences in shaping teacher agency. Their findings underscore the importance of fostering teacher agency at multiple levels to uphold the integrity and efficacy of education systems amidst ongoing reforms.