Environmental problems continue to intensify. Yet, despite scientific consensus on threats such as climate change, broadscale public engagement with the issue is elusive. In this paper, we focus on childhood formative experiences and the extent to which they are correlated with environmental engagement. We consider two forms of environmental engagement: civic engagement, measured in hours per month devoted to an environmental protection cause, and private-sphere green behavior. Past studies about significant life experiences have shown that formative experiences, especially in childhood, correlate with environmentally sensitive attitudes and vocations in later life. However, we know less about the formative life events experienced by contemporary environmentally engaged persons. Looking at a nationally representative sample of American adults (n = 449), we find that childhood trauma predicts both civic engagement and green behavior. We also find that childhood experiences in nature and childhood travel experiences predict green behavior but not civic engagement.