In recent decades, observers of Congress have devoted increasing attention to the phenomenon of the revolving door, whereby members of Congress and staffers go on to careers in lobbying. This practice raises a number of normative concerns that are perhaps most heightened when it comes to the lobbying activities of members of Congress themselves. In this article, I examine the factors determining which former members go through the revolving door, and find that members with central network positions and highly effective legislators are more likely to become lobbyists. I then examine the extent to which members-turned-lobbyists have an impact on bills in Congress. I find evidence that lobbying by former members increases a bill’s probability of progressing and some evidence that highly effective legislators also go on to become more effective lobbyists. Taken together, these findings support conventional wisdom that former members become some of the most influential lobbyists.