Ms. Brennan, whose debut is set for Sunday, joined CBS News in 2012 after a decade in financial journalism, working as an anchor and correspondent at Bloomberg Television and CNBC. She said in an interview on Thursday that she hoped “Face the Nation” would offer a dose of civility in a highly charged political moment.
“Sometimes it’s overwhelming for viewers, because there is such an unrelenting news cycle right now,” Ms. Brennan said. “This is a place where we need to have some perspective, have a civil conversation and take a step back.”
At CBS, Ms. Brennan has reported on the Trump White House and helped lead coverage of major international stories, including diplomatic relations between the United States and Cuba, nuclear negotiations with Iran, chemical weapons attacks in Syria, and nuclear tensions in North Korea. She recently interviewed Rex Tillerson, President Trump’s secretary of state, for “60 Minutes.”
“A lot of people in Washington have covered politics; not as many people have covered Trump,” David Rhodes, the president of CBS News, said in an interview. “Margaret has a curiosity about foreign affairs, but also politics and the Trump administration, and even business and finance, that gives her a really wide range.”
A plum assignment in network news, Mr. Dickerson’s spot on “Face the Nation” was the subject of some in-house jockeying at CBS. Among the contenders were Major Garrett, the network’s chief White House correspondent and a familiar figure to those who watch the daily televised White House briefings, and Nancy Cordes, another of the network’s lead Washington reporters.
Ms. Brennan, who grew up in Danbury, Conn., studied foreign affairs and the Middle East at the University of Virginia and spent time in Jordan, where she learned to read and speak Arabic. Her first job in journalism was an internship at CNN in Atlanta.
It was Ms. Brennan’s mother who suggested that she pursue a career in television news.
“My mom said, ‘You should try that out,’” Ms. Brennan recalled. “‘You’re always talking to the TV screen, that they didn’t give the context on this or that. Why don’t you try to do it yourself?’”