Kirby spent the summer of 2000 playing in the Lancashire and Ribblesdale League while working as a lino salesman for West Cotes Flooring in Leicestershire, at the age of 24 he had written to Stephen Oldham director of Yorkshire County Cricket Club's academy asking for a chance to resurrect his cricket career. After a net session Yorkshire offered Kirby the chance of some games in the second XI at the start of the 2001 season and after taking 12 wickets in 2 matches he entered into contract discussion but by June was back at his flooring job again. On 7 June 2001, Kirby received a phone call from Oldham asking if he could come to play for Yorkshire first XI the following day as a substitute for Matthew Hoggard in their Championship fixture against Kent. After being given time off from his day job Kirby took 7 for 50 from 24 overs to win the match for Yorkshire, the best by a Yorkshire debutant in Championship cricket since Paul Hutchison in 1997. His third match saw him face his old county Leicestershire, again Kirby was instrumental in Yorkshire's innings victory with match figures of 12 for 72. By the end of the season, Kirby had taken 47 wickets at 20.85 and played an instrumental role in Yorkshire becoming County Champions for the first time in 33 years. His performances earned him place in the first England Academy squad, based in Australia, in November 2001.