Chancellor attended the University of Illinois Navy Pier campus, completing the last two years of instruction at the University of Illinois at Urbana–Champaign in 1949.
Originally a copy boy at 14 for the Chicago Daily News and hired in 1947 to be a reporter for the Chicago Sun-Times, he started his career in local television in Chicago, eventually turning to national television news as a correspondent on NBC's evening newscast, the Huntley-Brinkley Report.

Chancellor covered issues of national importance while on The Huntley-Brinkley Report.

Chancellor covered the 1957 integration of the Little Rock Central High School, where a young Black girl, Elizabeth Eckford, wanted to attend an integrated school.
Chancellor's coverage showed the white mob that surrounded her.
After Chancellor began to cover the Little Rock story, segregationists followed him around town in anger.
 
Chancellor spent a number of years as a foreign correspondent in Europe, with postings in Vienna, London, Moscow, and Brussels (NATO Headquarters).

In July 1961, Chancellor replaced Dave Garroway as host of NBC's Today program, a role he filled for fourteen months.
Never comfortable with the soft news focus of Today, Chancellor asked for, and was granted, a release from his contract with the show in the summer of 1962.
He left the program in September, and assumed a role as political correspondent for NBC News.
He, Frank McGee, Edwin Newman, and Sander Vanocur comprised a team that covered the national political conventions in the 1960s so well, they were dubbed by industry observers as the "Four Horsemen."

At the 1964 Republican National Convention, he was arrested for refusing to cede his spot on the floor to "Goldwater Girls," supporters of the Republican presidential candidate, Barry Goldwater.
When security came to get him, he was forced to sign off: "I've been promised bail, ladies and gentlemen, by my office.
This is John Chancellor, somewhere in custody."
He then became the director of the Voice of America in 1965, at the request of President Lyndon Johnson, a spot he held until 1967.
Chancellor attended the University of Illinois Navy Pier campus, completing the last two years of instruction at the University of Illinois at Urbana–Champaign in 1949. Originally a copy boy at 14 for the Chicago Daily News and hired in 1947 to be a reporter for the Chicago Sun-Times, he started his career in local television in Chicago, eventually turning to national television news as a correspondent on NBC's evening newscast, the Huntley-Brinkley Report.
Chancellor covered issues of national importance while on The Huntley-Brinkley Report.
Chancellor covered the 1957 integration of the Little Rock Central High School, where a young Black girl, Elizabeth Eckford, wanted to attend an integrated school. Chancellor's coverage showed the white mob that surrounded her. After Chancellor began to cover the Little Rock story, segregationists followed him around town in anger.  
Chancellor spent a number of years as a foreign correspondent in Europe, with postings in Vienna, London, Moscow, and Brussels (NATO Headquarters).
In July 1961, Chancellor replaced Dave Garroway as host of NBC's Today program, a role he filled for fourteen months. Never comfortable with the soft news focus of Today, Chancellor asked for, and was granted, a release from his contract with the show in the summer of 1962. He left the program in September, and assumed a role as political correspondent for NBC News. He, Frank McGee, Edwin Newman, and Sander Vanocur comprised a team that covered the national political conventions in the 1960s so well, they were dubbed by industry observers as the "Four Horsemen."
At the 1964 Republican National Convention, he was arrested for refusing to cede his spot on the floor to "Goldwater Girls," supporters of the Republican presidential candidate, Barry Goldwater. When security came to get him, he was forced to sign off: "I've been promised bail, ladies and gentlemen, by my office. This is John Chancellor, somewhere in custody." He then became the director of the Voice of America in 1965, at the request of President Lyndon Johnson, a spot he held until 1967.
John Chancellor