He returned to the Bradford Bulls in 2003 and found a place in the first team after a long term injury to Michael Withers, making 20 appearances in the title-winning Bradford Bulls team, including being in the 2003 Super League Grand Final against Wigan Warriors in which he scored a try. Reardon scored a try and won the Harry Sunderland Trophy for his man of the match performance at the Old Trafford showdown. Reardon represented England 'A' while at the Bradford Bulls in the 2003 European Nations Cup against Wales and France. Having won Super League VIII, Bradford played against 2003 NRL Premiers, the Penrith Panthers in the 2004 World Club Challenge. Reardon played from the interchange bench in the Bradford Bulls' 22–4 victory. Later that year Reardon played for the Bradford Bulls as a in their 2004 Super League Grand Final loss against the Leeds Rhinos. He broke into the Great Britain squad for the 2004 Tri Nations series, and scored four tries in the tournament. Reardon won caps for Great Britain while at the Bradford Bulls in 2004 against Australia (3-matches), and New Zealand (2-matches), and won caps for England while at the Bradford Bulls in 2005 against France, and New Zealand (interchange/substitute). He missed the back end of 2005's Super League X with injury but made the England team at the end of the season, and toured Australia and New Zealand as a stand-by for the Great Britain squad in 2006. Paul Cullen described as the 'best kick returner in Super League' during 2006's Super League XI, Reardon was the Warrington Wolves leading tackle-buster with 66 in his first year at the club.