[2] Leo was raised in Teaneck, New Jersey, and attended Regis High School in New York City on scholarship, graduating in 1952.
[2][3] After his graduation in 1957, he went back to his home state and covered the criminal courts for the Bergen Record of Hackensack, New Jersey, for three years.
In his weekly column for the National Catholic Reporter, titled "Thinking It Over", he pushed hard for free speech and greater openness in the church.
[4] When Daniel Berrigan, a flamboyant anti-Vietnam-war Jesuit, was exiled to Latin America and put under a vow of silence, Leo broke the story in his column.
He returned to journalism and inaugurated the Press Clips column in The Village Voice[7] and served as book editor of the sociological magazine Society.
[8] Leo worked at Time from 1974 to 1987,[9] writing the behavior section which covered psychology, psychiatry, feminism and intellectual trends.
The column focused mainly on social and cultural issues, most commonly political correctness, but also advertising, movies, language, the news media, higher education, pop psychology and the self-esteem movement.
[2] Leo served on the board of advisers of the Columbia Journalism Review for a decade and on the church-state committee of the American Civil Liberties Union for two years.