This dissertation builds off of literatures which emphasize the group-basis of public opinion. Here, I position age and youth as a key social identity and then present my theory of youth consciousness and intergenerational solidarity as a novel pathway to American political behavior. I argue that youth who hold more in-group favorability toward those inside of their own young age group as well as older adults who hold more favorability toward the young outside of their own age group increases the likelihood of supporting a youth-salient issue agenda. I then develop four measures of youth attitudes which gauge individuals’ affect toward young people, which ranges from more positive feelings to more negative feelings toward them. After validation of these measures, survey research demonstrates how youth attitudes are related to support for a youth-salient issue agenda. I find that those with more positive affect toward the young are more likely to support policies that have a youth-centered focus including issues of the environment, healthcare, and immigration. In addition to examining the relationship between youth attitudes and partisanship, I find that individuals with more positive feelings toward young people are more likely to support elected officials, particularly those who specifically advocate for the interests of the young. Further, in a series of survey experiments, I find that youth attitudes can become an even stronger predictor of youth-salient public opinion when policy issues are framed around their disproportionate impact on young people. The dissertation closes with a discussion of how this theory and evidence for youth consciousness and intergenerational solidarity informs recent event such as youth-led political movements which include older adults who have come to advocate with the young. The dissertation, overall, makes contributions to studies revolving around social identity theory, identity politics, public opinion, and political behavior in American Politics.