Japan, a fast-ageing liberal democracy, features notably low youth representation with older politicians being significantly over-represented. This case study explains the low number of young members of the parliament and explores Japanese youths’ political engagement. By drawing on the “vicious cycle of youth political alienation” as conceptualized by Stockemer and Sundström, we identify four key factors contributing to low youth representation: a) political interest and youth issues, b) political participation and self-efficacy, c) trust in political institutions, and d) the dominance of the Liberal Democratic Party (LDP). With a mixed-method approach, we look behind the comparatively low levels of political interest, reported self-efficacy and voter turnout among young people, directly linking the extent of the LDP’s legacy and a mismatch in issue alignment to youth (under)representation. Despite the relatively bleak outlook on youth representation in Japan, there remains potential for both meaningful change and further research.