[2] He won a gold medal at the 1992 World Rowing Championships in Montreal while competing in the Junior Men's Eight.
While at Washington, Callahan won four Pacific-10 championships, earned the Ky-Ebright trophy in the Men's Varsity Eight three times, and was both captain and commodore of the 1996 team.
In 1995 and 1996 his crews won a bronze and silver medal in the Men's Varsity Eight at IRA National Championships.
Under Callahan, the UW men have won the James Ten Eyck Memorial Trophy (for overall points leader at IRAs) in 12 of his 13 seasons, including the last eight of a nine-year streak (2007–15) by Washington, also unprecedented in the history of the IRA Regatta.
During Callahan's tenure, Washington has also sent six boats to the prestigious Henley Royal Regatta in England.