Todays news media environment incentivizes gatekeeping practices that lead to a bias toward content containing partisan conflict and ideological extremity. Using a content analysis of 46,218 cable and broadcast television news transcripts from the 109th through 112th Congresses, we examined the frequency with which members of Congress appeared on cable and broadcast news. When we modelled on-air statements by members of Congress as a function of legislator and institutional characteristics, we revealed a gatekeeping function that vastly overrepresents extreme partisans on both sides of the aisle. The effect is largely consistent for network and cable outlets alike, suggesting that gatekeeping processes under both market and advocacy models bias content towards the extreme and conflictual. This finding is particularly important in light of recent evidence linking media-driven misperceptions about polarization to partisan-ideological sorting and negative political affect in the electorate.