Purpose: This paper aims to trace how emotion shapes the sense that is made of politics and how politicization can remake and re-mark emotion, giving it new meaning in context. This paper brings together theories of politicization and emotional configurations in learning to interrogate the role emotion plays in the learning of social justice activists. Design/methodology/approach: Drawing on sociocultural learning perspectives, the paper traces politicization processes across the youth climate movement (using video-based interaction analysis) and the animal rights movement (using ethnographic interviews and participant observation). Findings: Emotional configurations significantly impacted activists' politicization in terms of what was learned conceptually, the kinds of practices -- including emotional practices -- that were taken up collectively, the epistemologies that framed social justice work, and the identities that were made salient in collective action. In turn, politicization reshaped how social justice activists made sense of emotion in the course of activist practice. Social implications: This study is valuable for theorizing social justice learning, so social movement facilitators and educators might design spaces where learning about gender, racialization, colonialism and/or human/more-than-human relations can thrive. By attending to emotional configurations, this study can help facilitate a design that supports and sustains learning for justice. Originality/value: Emotion remains under-theorized and under-analyzed in the learning sciences, despite indications that emotion enables and constrains particular learning opportunities. This paper proposes new ways of understanding emotion and politicization as co-constitutive processes for learning scientists interested in politics and social justice.