Schieffer is one of the few journalists to have covered all four of the major Washington national assignments: the White House, the Pentagon, United States Department of State, and United States Congress. His career with CBS has almost exclusively dealt with national politics.
On October 13, 2004, he was the moderator of the third presidential debate between President George W. Bush and Senator John Kerry in Tempe, Arizona. On October 15, 2008, Schieffer moderated the third presidential debate between Senator Barack Obama and Senator John McCain.
Schieffer was anchor of the Sunday evening news broadcast from 1973 to 1997 and of the Saturday evening news broadcast from 1977 until 1996. Between 1970 and 1974, he was assigned to the Pentagon, from 1974 to 1979 he was CBS's White House correspondent, and in 1982 he became Chief Washington Correspondent in addition to his anchor duties.
In the wake of Dan Rather's controversial retirement, he was named interim anchor for the weekday CBS Evening News. He assumed that job on March 10, 2005, the day following Rather's last broadcast. Under Schieffer, the CBS Evening News gained about 200,000 viewers, to average 7.7 million viewers, reversing some of the decline in ratings that occurred during Rather's tenure; while "NBC Nightly News" was down by 700,000 viewers, and ABC's World News Tonight lost 900,000. Some of this was attributed to the Schieffer family's closeness with President George W. Bush; Bush had previously refused to grant an interview to Rather. Schieffer closed the gap with ABC's World News Tonight when co-anchor Bob Woodruff was injured in late January 2006. He made his last CBS Evening News broadcast on August 31, 2006, and was replaced in the anchor chair by Katie Couric. On Couric's second broadcast, he returned to provide segments for the evening news as Chief Washington Correspondent.