Loneliness is known to be a major health concern globally. However, although there is a growing body of research on loneliness in adults, it is less studied in children. Further, very few studies have considered the long-term impact of experiences of being alone in early life on adults. This study explored the construct of aloneness in children using a retrospective design. It asked 70 adults to describe their high and low point stories from childhood. Analysis of the stories using reflective thematic analysis identified four aloneness constructs: emotional loneliness, social loneliness, quasi-existential loneliness and solitude. Risk and protective factors and related constructs for loneliness in childhood were also identified: home difficulties, life events, peer difficulties and emotional turmoil; and natural environment, independence, special occasions and stability. The study provides a framework for a holistic construct of aloneness in childhood, and highlights how developing a strong sense of identity and a positive attitude towards aloneness in early years may help to develop social and policy interventions to boost wellbeing across the lifespan.