Mark Whitwill was born in 1857 in Bristol, Gloucestershire, England.

He was a shipowner, shipbroker, and philanthropist. He worked at Mark Whitwill & Son, Shipowners and Brokers and General Shipping Agents, a firm established by his father, Mark Whitwill (1826-1903), in Bristol in 1831. They were managers of Great Western Line of Steamers, Bristol & New York, and agents for the Royal Mail Steam Packet Company, the Allan Line of Steamers to Quebec, and the National Line of Steamers to New York.

In 1883, he married Emma Reece May (1860–). He died on December 5, 1921, in Keynsham, Somerset, England.

William Peter Olcott Whitwell received his M.D., C.M. from McGill in 1860. The son of a clergyman, he resided and practiced in Philipsburg, QC.