Sheppard was a true Renaissance Man: successful as an artist, teacher, author, yachtsman, navigator and yacht designer. He studied painting under the excellent M.F.H. de Haas in New York City, and received his formal art training at the Cooper Union.
He was born on the Delaware River in Greenwich, New Jersey, a place associated with ships and shipping since colonial times. There his father, a lumbership captain, often took his young son along the river where the developing artist studied the varied moods of the sea.
It is this characteristic of Sheppard's work, the capture of the emotional face of the sea, along with his unerring accuracy in rigging and ship details, that earned him many commissions for illustrations in such periodicals as The Brooklyn Eagle, The New York Herald Tribune and The New York Sun.