James Knowles suggests

I currently think of him as a French Canadian voyageur who became intrigued by the southerly waters and paddled his canoe down from Lake Champlain, down the Hudson River to its mouth and then making an unfortunate turn down what is now the East River. He became embroiled in the confluence of water flows as the East River meets the influx from Long Island Sound. He was dumped into the waters along with his eight Indian paddlers and an old friend named Murray. Everything lost, wet and bedraggled, they made land about where the United Nations stands so monarchically today.

I refer to him as Roger with a French accent.

Perhaps his name was derived from the marriage of a Roger and a Smith, and originally Roger-Smith was a woman. The product of a French and English love affair on an island up in the great St. Lawrence River, the highway to the American Heartland. Her father Adolfe Roger would have married Jane Smith in 1668. Their daughter, the original Roger-Smith, was named Lily and bore a marvelous but intenerate adventurer and the son was therefore named after his mother. Jean Roger-Smith anglicized his name to John after the East River Debacle around the turn of the century (ca.1701).