John Simon, known equally for his considerable erudition, his longevity as a critic, and his sometimes vituperative style, died November 24. He was 94.

Mr. Simon's reputation as an aggressive drama critic, with a tendency for acerbity, was forged early on. Joseph Papp wrote New York Magazine a letter in 1972 saying Simon suffered from the effects of a "benevolent mother who undoubtedly fussed all over her precocious offspring." Papp would in 1989 demand Simon's dismissal. Edward Albee—a frequent sparring partner—wrote in the New York Times in the mid-'60s, "Mr. Simon's disapproval of my plays has been a source of comfort to me over the years and his dislike of A Delicate Balance gives me courage to go on, as they say."

Mr. Simon was born Ivan Simmon May 12, 1925, in the former Yugoslavia and never lost his Eastern European accent, moved with his family to the United States in 1941. While a student at Harvard, he was hired by playwright Lillian Hellman to do a translation of Anouilh's The Lark. Reportedly, she later refused to pay him because he had typed it in the wrong format.

He began by writing critiques for Commonweal and the Hudson Review. He also reviewed for New York's Channel 13, but was forced out in 1967 because the station considered his notices misanthropic. Sometimes, even his fellow critics thought he went too far. In 1969, the New York Drama Critics Circle voted 10 to 7 to refuse him membership. The following fall, the body relented and allowed him in. In 1980 an ad appeared in Variety, signed by 300 people, protesting his reviews as vicious and racist.

In perhaps the most famous incident of retaliation against Simon's harsh words, actor Sylvia Miles, upon encountering the critic in a restaurant on October 7, 1973, dumped a plate of food over his head.

Mr. Simon took all of the above in seeming stride, often joking about the outsized reaction he provoked in the theatre community. And he was not without supporters. His fans applauded the intelligence of his writing; the deep knowledge of the classics and of languages that informed his reviews (he was known to correct playwrights' grammar and word usage); and his bravery in expressing his opinions in no uncertain terms. The divided nature of his writings—part intellectual, part character assassin—was summed up in an essay by Robert Brustein, in which he referred to the "good John Simon" and the "bad John Simon."

He served as New York Magazine's theatre critic for 37 years until his dismissal in 2005, at which point he joined Bloomberg. Upon leaving that post in 2010, he created his own website, UncensoredJohnSimon.blogspot.com. His last post there was October 27.

His writing has been collected in several books, including three volumes of his collected works from Applause Books: one on his theatre writing, one on music, and one on film.

He is survived by his wife, Patricia Hoag-Simon.