Atkinson was born in Melrose, Massachusetts, where as a boy he printed his own newspaper (using movable type), and planned a career in journalism. He graduated from Harvard University in 1917, and worked at The Springfield Daily News and The Boston Evening Transcript, where he was assistant to the drama critic. In 1922 he became the editor of the Times Book Review, and in 1925 the drama critic.

Atkinson quickly became known for his commitment to new kinds of theater—he was one of the first critical admirers of Eugene O'Neill—for his interest in all kinds of drama, including off-Broadway productions, and for his wit. In 1928 he said of the new play The Front Page, "No one who has ground his heels in the grime of a police headquarters press room will complain that this argot misrepresents the gentlemen of the press." Atkinson had covered the police beat for the Evening Transcript.

After the bombing of Pearl Harbor in 1941, Atkinson attempted to enlist in the Navy, but was refused. He requested a reassignment to war coverage, and the newspaper sent him to the front lines in China, where he covered the war with Japan until 1945. He stayed only briefly in New York before being sent to Moscow; his work as the Moscow correspondent for the Times earned him a Pulitzer Prize in 1947.

After returning from the Soviet Union, Atkinson was reassigned to the drama desk, where he remained until his retirement in 1960. He is given much credit for the growth of Off-Broadway into a major theaterical force in the 1950s, and has been cited by many influential people in the theater as crucial to their careers. David Merrick's infamous spoof ad for Subways Are For Sleeping—in which he hired seven ordinary New Yorkers who had the same names as prominent drama critics to praise his musical—had to wait for Atkinson's retirement, because Merrick could not find anyone with the right name. There was only one Brooks Atkinson in New York City.