Hackl won a total of 22 medals at the FIL World Luge Championships, including ten golds (Men's singles: 1989, 1990, 1997; Mixed team: 1991, 1993, 1995, 2000, 2001, 2003, 2005), ten silvers (Men's singles: 1991, 1993, 1995, 1996, 2001, 2004, 2005; Men's doubles: 1987, Mixed team: 1996, 1997), and two bronzes (Men's singles: 2000, Mixed team: 1999).