[1][2][3] He attended Elgin Community College[1] before transferring to American University in Washington, D.C., where he earned a degree in journalism and was editor-in-chief of the student newspaper, The Eagle, for the 1966–1967 academic year, as well as the paper's movie critic.

He served as the station's disc jockey, local news reporter, writer and announcer, on both the AM and FM bands.

[1] He joined The Washington Post as a writer in the Style section in 1972, was named chief television critic in July 1977, and was appointed TV editor in June 1979.

[7] His blunt style could polarize; Forbes Media Guide Five Hundred, 1994 wrote: "Forget the middle ground, Shales either loves it or hates it – and his reviews of TV shows and personalities are often unabashed paroxysms of that love or hate.... Like the medium he covers, Shales turns out fast-paced and amusing fare that often lacks depth".

Daily Herald film critic Dann Gire who founded and served as president of the Chicago Film Critics Association, described him as setting a standard with writing that was "incredibly funny, creative, inventive and smart" and with a style more akin to a barroom discussion with readers than a lecture.

[3] In 1988, Shales received the Pulitzer Prize for Criticism for his work at The Washington Post,[4] including his coverage of the Robert Bork Supreme Court nomination hearings.