Ed Sullivan, who could not sing, dance, or act, was television's greatest showman in its early years. For twenty-three years, from 1948 to 1971, he hosted America's premiere variety show every Sunday night on CBS, on which he introduced an eclectic array of talent that included everything from opera singers to dancing bears to Elvis Presley and the Beatles. Sullivan, a former newspaper columnist, appeared on the nation's television screens as a most untelegenic presence. He was everything that a professional television host is not supposed to be—awkward, stiff, and prone to frequent malapropisms.

His real talent was behind the scenes, as a man who had his finger on the pulse of America's cultural tastes. He understood instinctively that a variety show should present acts that would appeal to the various demographic segments of its...