The prevalence of instrumental and emotional support received was investigated, and several psychosocial characteristics were studied in a Spanish population of all ages (10–85 years) and different social groups, by using an 88-item online questionnaire, with a total of 2013 respondents. Participants reported on the instrumental and emotional supports they receive, and on a set of psychosocial variables (emotion management, motivation, self-efficacy, social and communication skills, and social support), as well as their sociodemographic data; all of which were considered as contributions to a sustainable world. Instrumental and emotional supports for sustainability were significantly less prevalent among older participants, men, people with low educational levels, low autonomy levels, retired individuals, and those with a low-income level. Older and female participants were able to manage their own and other peoples’ emotions significantly more frequently. Participant motivation was less prevalent among the participants with low autonomy levels and low-income levels. Younger participants with low autonomy levels were significantly less able to perform activities related to their self-efficacy. Extreme age groups, those with higher educational levels, singles, and those living alone, reported feeling lonely more often. These results help identify sociocultural characteristics of adults with low social participation, which is critical for developing useful strategies to promote community engagement and related benefits for older adults.