Reeves received his M.E. from Stevens Institute of Technology in 1960. After graduating, he spent a year working as an engineer for Ingersoll-Rand, after which he moved to journalism. From 1961-1965, Reeves co-founded and worked for the Phillipsburg Free Press (New Jersey), then worked for Newark Evening News and the New York Herald Tribune before being assigned the post of Chief Political Correspondent for The New York Times in 1966. In 1971, Reeves left the Times to lecture at Hunter College.

Reeves' opinions generally have a liberal bent—he opposed the war to topple Saddam Hussein as "stupid and unnecessary" (column, March 19, 2003)—but shuns "extreme" leftist positions. He pays close attention to happenings overseas and often fills his columns with explanations of current trends based on history. Many of his columns focus on the world's reaction to the United States' political actions.

He has also published nine books, mostly about American politics. In 1993, he appeared in the film Dave, one of several journalists who played themselves in the film.

Reeves' weekly column, carried by Universal Press Syndicate, has appeared in more than 160 newspapers across the United States since 1979. He is married to Catherine O'Neil, founder of the Women's Commission for Women and Children Refugees. Together they have five children and divide their time between Los Angeles and New York City.

In October 2004 in an article titled "To begin with the President is a fool", he shared his belief that John Kerry would win the 2004 presidential election (he lost). In this article, he indicates that he (Reeves) voted absentee for the Democrat. He then shares his bias by saying: "Biased? Of course. That's why I write this column: to share my bias. I am always amazed when I get letters, many of them, accusing me of being a "liberal" or, a lot worse, an "elitist." Yes, I am. Hello!"

In November 2005, Reeves theorized that George W. Bush could be regarded as the worst president in U.S. history, noting: "The History News Network at George Mason University has just polled historians informally on the Bush record. Four hundred and fifteen, about a third of those contacted, answered making the project as unofficial as it was interesting. These were the results: 338 said they believed Bush was failing, while 77 said he was succeeding. Fifty said they thought he was the worst president ever."