Emerging adulthood is a critical developmental stage, marked by transitions, identity exploration, and psychosocial vulnerability. The experience of citizenship, through belonging, participation, and access to urban resources, can significantly influence how emerging adults navigate the challenges and opportunities of this life phase. In this study, we investigated civic happiness, defined as psychological well-being and satisfaction with various life domains in relation to one's community, using a representative sample of citizens (aged 18+) from the city of Turin. The main aim was to map levels of happiness and mental well-being, along with their key antecedents, across different age groups. A total of 2,402 individuals completed a self-report questionnaire. The age distribution was as follows: 18-29 years (18.7%), 30-49 years (32.8%), 50-64 years (26.0%), and over 64 years (22.5%). Additionally, 53% of participants were female. Analyses were conducted using SPSS 28. Findings revealed that emerging adults reported significantly lower levels of mental well-being (measured through the Mental Health Continuum - Short Form) and happiness compared to older age groups. Regression analyses (adjusted R² = .29) identified three key predictors of mental health within emerging adults' group: (1) satisfaction with social relationships within one's neighborhood, (2) satisfaction with one's family situation, and (3) feeling accepted and able to participate in and contribute to the functioning of the community. Despite some study's limitations, these results highlight the importance of community-based and relational factors in shaping the psychological well-being of emerging adults in urban environments. They also underscore the need for targeted local policies and interventions that foster social inclusion, educational support, and meaningful opportunities for civic participation. Addressing these specific needs may play a crucial role in preventing psychological distress and enhancing mental health outcomes among young urban citizens.