Leonhardt has also won fifteen medals at the ICF Canoe Sprint World Championships with six golds (K-4 200 m: 2005, 2007, 2009; K-4 500 m: 2005, 2007; K-1 4 x 200 m: 2011), eight silvers (K-2 1000 m: 2009, 2010, 2013; K-4 200 m 2006, K-4 500 m: 2006, 2009, 2011; K-4 1000 m: 2006), and a bronze (K-4 1000 m: 2005).