Using structural regression analyses, data from the U.S. 2017 Program on International Assessment of Adult Competencies (PIAAC) background survey were examined to test the effect of informal learning (observed through everyday activities, such as reading the newspaper or using the Internet to find information about issues) on civic engagement (observed through volunteerism, political self-efficacy, and social trust). Results showed a positive relationship between informal learning and civic engagement with ICT-related activities having the strongest effect. This effect was mediated by presence of a lifelong learning mindset (LLM) observed through traits related to learning motivation and persistence. Although a majority of respondents indicated agreement with LLM attitudes and behaviors, they also reported low frequencies of volunteerism and less agreement with political self-efficacy and social trust statements. The need for governments to provide meaningful opportunities for citizens to contribute their knowledge to the community, thus enabling a learning democracy, is discussed in light of these findings.