Walter Lewis was a member of the Toronto Argonauts Rowing Club when he was selected to represent Canada in the coxed eights at the 1908 Summer Olympics. There, alongside Gordon Balfour, Becher Gale, Douglas Kertland, Charles Riddy, Irvine Robertson, Geoffrey Taylor, Julius Thomson, and Joe Wright, Sr., he was defeated in the semifinals by the eventual gold medal-winning Leander crew from Great Britain and settled for bronze. Two years earlier, Lewis had helped the Argonauts win the junior eights at Canada’s Henley Royal Regatta. At the onset of World War I he joined the British Infantry and served with distinction, earning a Military Cross and Bar for his actions overseas, and leaving the army with the rank of Lieutenant.