The rapid shift to remote teaching during the COVID-19 pandemic forced teachers into unfamiliar new territory, with schools closing their doors. The experience involved altering the usual ways of teaching and learning as well as changing interaction patterns with students and colleagues. The aim of this chapter is to analyze how teachers perceived these changes in their work and how they enacted their professionalism and resilience in disruptive times. It reports on data from research conducted on 2192 teachers in Portugal through an online survey. Findings highlight the intensity of the experience of teaching during the pandemic, the mobilization of personal, professional and contextual resources to deal with the challenges and difficulties encountered, and the crucial importance of collaboration and collegiality together with one’s core professional values as a teacher. There is a need for a more comprehensive and inclusive perspective on teachers’ professional development that promotes collective construction of professional knowledge and the creation of strategies that may boost collaborative professionalism and resilience, necessary for teachers to respond to the complex professional worlds in which they work.