Leo Wilkens was a rower from Malmö RK. Together with two of his club mates and two rowers from Helsingborgs RK, Wilkens took part in the 1912 Olympic Games in Stockholm as part of the Roddklubben af 1912 team. He coxed the Swedish inriggers coxed four which eliminated the two Norwegian boats in the first two rounds, but lost in the final against the Danish team from Nykjøbings paa Falster to win silver. He also coxed the Swedish eight. In this event the team of the Roddklubben af 1912 lost to the eventual silver medallists from the New College, Oxford in the quarter-final.
A few years after the Olympics, moved to the United States and lived there in New York and in his final years in Connecticut. He retained, however, his Swedish citizenship. In the US, he made a career as a merchant and later became director of A. Johnson & Co Inc., the North American branch of a Swedish trading company. For his services he was appointed Knight of the Vasa Order in 1944. He was married to the Odessa born Maria M. Caravias from a Greek family. The marriage remained childless.