He returned to fencing three years later and won a gold medal at the 2003 Pan American Games, and his first national foil championship in 2004.

Kellner rallied from a 0–6 and 1–7 deficit in his semifinal against Jed Dupree, countered with 7 straight touches, edging ahead to 8–7.

[9][10] Kellner decided to skip the 2005 World Cup in Vancouver and the US nationals so he could compete in the 2005 Maccabiah Games in Israel.

He led the U.S. delegation's march into the Ramat Gan stadium alongside legendary swimmers Mark Spitz and Lenny Krayzelburg.

[12] Kellner won the silver medal at the 2005 Maccabiah Games, losing to Israel's Tomer Or 15–9.

[13][14][15][11] Kellner won a team silver medal at the 1999 Pan American Games in Canada.