Across democracies, elected officials are expected to represent their constituents, but how do legislators react to changes in their constituency? This core question of legislative responsiveness is examined in the context of the bicameral U.S. Congress where more than 100 legislators have served in both chambers since 1960. These chamber-changers provide a unique vantage point for examining constituency representation, including competing expectations based on the electoral connection and the ideological stability of legislative voting. Based on analyses of original data, I find overwhelming evidence of legislative responsiveness to both constituency change and constituency stability. Moreover, when legislators’ constituencies change, they respond by changing their behavior in ways that reflect both the direction and magnitude of constituency change.