[2] He made his international debut that year at the 1998 IAAF World Cross Country Championships, finishing 40th in the junior race.
[4] Slattery made his senior international debut at the 2003 World Championships in Athletics and ran a personal record time of 8:22.32 minutes in the heats.
[3] Slattery set a new best of 8:15.69 minutes at the 2007 Memorial Van Damme meeting (second fastest American that year) and was third in the steeplechase at the Prefontaine Classic.
[5] He came second at the 2008 Reebok Grand Prix in New York City with a run of 8:28.21 minutes, but failed to finish at the Olympic Trials final.
In 2011 he ran a season's best of 8:28.52 minutes at the Shanghai Golden Grand Prix, but pulled out of the steeplechase heats at the national championships.