Current cable documentary series such as Behind the Music and the E! network's True Hollywood Story wouldn't have come into being without Biography, the one that launched the genre in 1961.
Biography, produced by documentarian David L. Wolper for CBS, lasted 3 seasons (1961-4), narrated by newsman Mike Wallace. I recall seeing this in syndicated repeats as a youth, usually on a Sunday afternoon. However, those reruns eventually went away until the 80's, when the Arts & Entertainment Network, now known simply as A & E, acquired the series. The reruns, revived for a new generation, produced strong enough ratings to warrant A & E commissioning a full-on revival in 1987, and at one point, this incarnation of Biography would air six nights a week. A & E would later launch the Biography Channel as a spin-off from the series.
In between, CBS tried reviving it themselves with a short-flight relaunch in 1979, with actor David Janssen (ex-The Fugitive, Richard Diamond, etc.) as host-narrator, but it didn't take.
Let's go back in time with a sample from the original series, the first three minutes and change of an episode devoted to Pope Pius XII: