According to Jeffrey Ruoff 's 2003 account in "An American Family: A Televised Life," Gilbert was raised in upscale Woodmere on NY's Long Island. His father was a copyright lawyer, his mother a housewife. He attended Andover prep school, then Harvard. He served in the Navy in the early 1950s, working as a production assistant on instructional films. He then worked briefly as an editor on "The March of Time" newsreels before joining NBC's Victory at Sea (1952) TV) series.