Immigrant political organisations in the United States have traditionally built political power by claiming to legitimately represent an ethnically defined group. However, the emergence of a number of multi-ethnic, class-based organisations over the last two decades has challenged this assumption, while raising questions about the ability of the institutional context to accommodate organisational change. Building on a neo-institutional theory of legitimacy, I examine the diverging legitimating strategies employed by two long-standing immigrant organisations based in Los Angeles (LA): the Korean Resource Center (KRC) and the Koreatown Immigrant Workers Alliance (KIWA). Through grant applications, organisational archival data and qualitative interviews, I show how KRC and KIWA, two groups embedded in the same sociopolitical context, have built unique yet equally successful legitimating accounts by adopting different organisational logics, one broadly based on ethnicity and one on class and multi-ethnicity. I suggest that KIWA and KRC's ideological differences, and their reliance on a different core of supporters -ethnic-oriented for KRC, labour-oriented for KIWA -drove the organisations towards distinct, yet partially overlapping subfields. By discursively mobilising those connections, and by actively shaping the surrounding organisational environment, both KRC and KIWA were able to incorporate in the broader non-profit advocacy sector in LA.ARTICLE HISTORY