This dissertation project explores how elected legislators appease different segments of society when confronted with conflicts of interests. I demonstrate that legislators tailor their actions based on different levels of constituency issue attention, respond to multiple interests by behaving strategically across different stages of the legislative process, thus position themselves in the most favorable light. Findings from this project have implications for legislative representation, interest group politics, and political engagement. Specifically, the dissertation takes the format of three papers and tackles the research topic from three distinct and relevant angles. The first paper focuses on the effect of constituency issue attention on legislative behavior, including bill sponsorship, floor debate, and roll call votes. I argue that, when constituencies pay more attention to a particular policy issue, legislators are likely to be more diligent by participating more in the legislative process, and more responsive by better reflecting district preference in their roll call votes. Using the 2006 Cooperative Congressional Election Study (CCES) data which directly measure congressional district-level constituency attention, I find that, as expected, legislators increase their levels of legislative activities when constituencies show higher level of attentiveness to a particular issue; yet contrary to expectation, legislators do not become more responsive in their roll call votes when constituency pay more attention. In the second paper, I take a nuanced look at congressional representation by examining how constituencies, sub-constituencies, and interest groups influence bill co-sponsorship, floor debate, and final votes. With a formal model explaining the mechanism through which voters and interest groups influence legislators' behavior, I propose a multiple representation theory that argues 1) the general geographic constituency is represented through legislative voting decisions, 2) the engaged sub-constituencies and organized groups are represented through non-voting activities such as co-sponsorship and floor debate. Focusing on the House of Representatives, I include in the data direct measures of public opinion (CCES, 2006-2008), interest group contributions, and legislative activities including an original dataset for floor debate participation. I find that the geographic constituency has a strong effect on voting decisions yet very limited effect on co-sponsorship or floor debate. It is interest group membership and PAC donations that affect co-sponsorship and debate. This multiple representation pattern is found on almost all of the domestic issues. On international issues such as trade policies, representatives' partisan affiliation and ideology are the most influential factors; constituencies, sub-constituencies, and interest groups are of secondary importance. The third paper studies representation in the Senate. I begin by applying the multiple representation theory in the context of senatorial politics and examining the same ten policy issues. The results suggest that while there are important similarities between representation in the Senate and that in the House, there are also significant differences. The most important difference is that there is not a multiple representation pattern in the Senate. Senators appear to be unresponsive to the geographic constituencies. To understand the senators' seeming unrepresentativeness, I take into consideration the senate's electoral and institutional features and hypothesize that state size, heterogeneity, and senate election cycles play a mediating role. The results suggest that senators' longer term is partially responsible for the unresponsiveness. Senators facing immediate re-election are in fact highly responsive to the geographic constituency, but the rest of the senators are not. This contrast between the House and the Senate on responsiveness clarifies the mechanism of legislative accountability: responsiveness is closely related to the electoral pressure from imminent re-elections, as observed in the behavior among House representatives and senators who were in the last two years of their terms; when the electoral pressure was not an immediate concern, other considerations such as partisanship and ideology take priority, as observed in the behavior among senators who were in the earlier years of their terms.