Born in New Jersey on April 16, 1976, Kellner began fencing after playing a video game called 'Summer Games,' in which he had difficulty with fencing. He asked his mother about the sport and soon began competing. A six-time member of the U.S. National team at the World Championships, Kellner finished second in the U.S. Nationals in 1997, 1998, and 2000. After failing to make the 2000 U.S. Olympic team, he took one year off before returning to active competition. He captured the gold medal at the 2003 Pan American Games and his first U.S. title in 2004.
A member of the 2004 U.S. Olympic fencing team, Kellner competed in the team and individual foil events. He is the top U.S. foil fencer (the last time an American male won an Olympic medal in the foil was Albert Axelrod). The American fencer received a bye in the first round due to his ranking as 25th in the tournament. Kellner faced Belgian Cedric Gohy in the round of 32 stage, and beat him convincingly. However, Richard Kruse (ranked 24) beat Dan in the round of 16, thus dashing his hopes of glory. In team foil, Kellner and Jon Tiomkin led the American men to a strong fourth-place finish.
After graduating from Columbia University in 1998, Kellner was a graphic designer for the Rosie O'Donnell Show and received two daytime Emmy nominations. The owner of Red Star Design, a graphic design company, Kellner also founded the Athlete Initiative, Inc., a nonprofit foundation. He told the USOC web site that I founded the organization to help raise money and support small sport athletes in their Olympic dreams.
Sources: Jews In Sports