When Baker was five years old, his father died. From that time on, he and his mother and one of his sisters moved frequently, living in Virginia, Maryland, and New Jersey. After graduating from Johns Hopkins University in 1947, Baker worked as a journalist for the Baltimore Sun (1947–54). He also wrote a lively weekly column, “From a Window on Fleet Street.” At the Washington bureau of the New York Times (1954–62), he covered the White House, the State Department, and the Congress. In the early 1960s he began writing the “Observer” column on the paper's editorial page. In this syndicated humour column he initially concentrated on political satire, writing about the administrations of U.S. Presidents John F. Kennedy (Kennedy, John F.), Lyndon B. Johnson (Johnson, Lyndon B.), and Richard M. Nixon (Nixon, Richard M.). Moving to New York City in 1974, he found other subjects to skewer, and in 1979 he won the Pulitzer Prize for commentary. His topics included tax reform, the artist Norman Rockwell (Rockwell, Norman), inflation, and fear.

Baker's Growing Up (1982), which recalls his peripatetic childhood, won the 1983 Pulitzer Prize for biography. A sequel, The Good Times, was published in 1989. Baker's other works include An American in Washington (1961), No Cause for Panic (1964), Poor Russell's Almanac (1972), and further collections of his columns. Baker also edited The Norton Book of Light Verse (1986) and wrote the book for the musical play Home Again, Home Again (1979). In 1993 he succeeded Alistair Cooke (Cooke, Alistair) as host of the television program Masterpiece Theatre. In that same year he published Russell Baker's Book of American Humor, which, following an illuminating introduction, gives its due to figures such as Benjamin Franklin (Franklin, Benjamin), Mark Twain (Twain, Mark), and James Thurber (Thurber, James). Baker's final “Observer” column for the New York Times appeared on Christmas Day, 1998. In 2002 he published Looking Back: Heroes, Rascals, and Other Icons of the American Imagination.