|Olympic medal record|
|Competitor for the United States|
|Silver||Seoul 1988||Soling class|
Altogether, Kostecki won ten world champion titles in different sailing classes, beginning with the Sunfish World Championships in 1982. At the 1988 Summer Olympics in Busan, South Korea, he finished in 2nd place in the Soling class along with his partners William Baylis and Robert Billingham. Also in 1988, he won the J/24 World Championships and the Soling Class World Championships. That year, he was then named “United States Rolex Yachtsman of the Year”.
In 1997, he won the Mumm 36 World Championship, the One Design 48 Championship, and the Malaysia Challenge Grand Prix. He also sailed the Whitbread Round the World Race in 1997/1998.
Kostecki became very popular in Europe as skipper and helmsman of the German yacht Illbruck in the Volvo Ocean Race 2001/2002. He led the team that was based in Leverkusen to an overwhelming victory in the arguably toughest sailing race around the world. Of notable interest was the fact that Illbruck set the world 24 hours speed record for monohulls. The record of 484 nautical miles was completed at 20:02 on April 30 during Leg 7 of the Volvo Ocean Race and was confirmed by the World Sailing Speed Record Council. This sparked an unprecedented sailing boom in Germany that led to thousands of sailing fans and Illbruck supporters awaiting Kostecki and his crew finishing their last leg from Gothenburg to Kiel. In 2002, Kostecki was named Rolex Yachtsman of the Year for the second time.
After a short employment with the BMW Oracle America’s Cup Team he joined team Ericsson for the next Volvo Ocean Race (2005/2006). He was also Ericsson’s designated skipper for the next Race (2008/2009) but resigned from his position in August 2007 for family reasons.
In 2008, the then three times America’s Cup winner Russell Coutts, who had just recently been appointed CEO of Larry Ellison's America’s Cup Team BMW Oracle Racing, hired Kostecki for his afterguard. The next America’s cup match took place between the defender, the Swiss team Alinghi, and BMW Oracle, in Valencia (Spain) in February 2010. With Kostecki as tactician, the American team won both races against the defender and thus brought back the oldest trophy in sports history to the United States after 15 years.
- Illbruck Sets 24-Hour Monohull World Speed Record, Cruising World magazine, retrieved 2011-01-10