Morgenstern graduated from Lehigh University in 1953. His first journalism experience was as news clerk at the New York Times. He then became foreign correspondent for the Times, based in Switzerland and France.

Morgenstern became an entertainment reporter for the New York Herald Tribune in 1959, later advancing to theater/music critic.

Beginning in 1965 until 1983 Morgenstern was film critic for Newsweek. From 1983 to 1988 he wrote a column for the Los Angeles Herald Examiner.

Morgenstern, presently based in Santa Monica, California, has written movie reviews for the Wall Street Journal since May 1995. His movie reviews appear each Friday in the "Weekend & Leisure" section of the newspaper, and he covers the movie industry in a column which appears every other Saturday. He also writes movie reviews for CNBC.

Morgenstern's writings have appeared in The New Yorker, The New York Times Magazine, Newsweek, Rolling Stone, Esquire, the Columbia Journalism Review and the Los Angeles Times Magazine. He has written several scripts for television.

Morgenstern co-founded the National Society of Film Critics.

He is renowned for his use of vocabulary and humor.

He received a Pulitzer Prize for Criticism in 2005, making him only the third film critic to win a Pulitzer for criticism, after Roger Ebert of the Chicago Sun-Times and Stephen Hunter of The Washington Post.

Morgenstern married Hollywood actress Piper Laurie on 21 January 1962. They had one child, Anna Grace Morgenstern. The couple divorced in 1981.