Does personal and family history influence legislative behavior in democracies? Linking members of Congress to the census, we observe countries of birth for members, their parents, and their grandparents, allowing us to measure ancestry for the politicians in office when American immigration policy changed dramatically, from closing the border in the 1920s to reshaping admittance criteria in the 1960s. We find that legislators more proximate to the immigrant experience support more permissive immigration legislation. A regression discontinuity design analyzing close elections, which addresses selection bias and holds district composition constant, confirms our results. We then explore mechanisms, finding support for in-group identity in connecting family history with policymaking. Holding fixed family history, legislators with more visible indicators of immigration based on surnames are even more supportive of permissive immigration legislation. However, a common immigrant identity can break down along narrower ethnic lines when restrictive legislation targets specific countries. Our findings illustrate the important role of personal background in legislative behavior in democratic societies even on major and controversial topics like immigration and suggest lawmakers' views are informed by experiences transmitted from previous generations.