Daniel Steven Kowalski is an Australian former middle and long-distance swimmer specialising in freestyle events. He competed in the Olympic Games in 200-, 400- and 1,500-metre individual freestyle events and in the 4×200-metre freestyle relay. At the 1996 Summer Olympics, he was the first man in 92 years to earn medals in all of the 200-, 400- and 1500-metre freestyle events. He was an Australian Institute of Sport scholarship holder.
Kowalski announced his retirement from competitive swimming on 8 May 2002. He studied sports marketing at Bond University, graduating in 2003. He was named as an assistant swimming coach at the University of Wisconsin–Madison in 2007, and also won the 2007 Pier to Pub 1.2 km open water swim held annually in Lorne, Australia.
In February 2004, he was the host of an overnight program on SEN 1116 with former South East Melbourne Magic basketballer Andrew Parkinson. In May 2007 Kowalski appeared as one of the celebrity performers on the celebrity reality singing competition It Takes Two.
In April 2010 Kowalski announced that he is gay. Kowalski says he was inspired to come out by Welsh rugby player Gareth Thomas, who announced the previous December that he was gay. He said “I felt really compelled to do it because it’s very tough to live a closeted existence”.