Kernochan was born on August 12, 1876 in Newport, Rhode Island. He was the son of attorney J. Frederic Kernochan and the former Mary Stuart Whitney (1849–1922), who were both prominent in New York society. He grew up at 11 East 26th Street, and had four siblings: Eweretta Kernochan (who did not marry), William Kernochan (who died in infancy), Mary Stuart Whitney Kernochan (who married Courtland Smith) and Whitney Kernochan (who married Helen (née Gaynor) Bradford, a daughter of New York City Mayor William Jay Gaynor).
