Klein was editor-in-chief at "Vox", later editor-at-large, and formerly wrote for and edited Wonkblog at "The Washington Post". He frequently provides political commentary on MSNBC's "The Rachel Maddow Show", "Hardball with Chris Matthews", and "The Last Word with Lawrence O'Donnell". He is a former contributor to "Countdown with Keith Olbermann". On March 14, 2013, "The Week" magazine reported that Klein was among those being considered to host MSNBC's yet-unnamed 8 p.m. weekday prime-time show that would replace "The Ed Show". Ultimately, the time slot was filled with "All In with Chris Hayes".