Vanderbilt was the youngest child of Seward and Lila Webb. He attended Yale, Oxford, and Harvard Law School. In 1912, he married Aileen Osborn, and they had five children, including Derick Webb. Vanderbilt pursued a law career, both in private practice and as special counsel to the Rockefeller Foundation. He also served briefly as a Captain in the American Expeditionary Force during World War I.