Leadbeater played for Yorkshire County Cricket Club as a middle-order batsman from 1966 to 1979, although he preferred to open the innings. His promise went largely unfulfilled. His average of 25.34 in 147 first-class matches (the norm for a county cricketer of the period was around 3000), scoring just one century.
The highlight of his playing career was a man-of-the-match winning 76 in the 1969 Gillette Cup Final, a match in which he was not expected to play.
Leadbeater broke a finger in the County Championship game the day before, and would have been omitted had Geoffrey Boycott not suffered a worse injury. Leadbeater said:
Leadbeater was to receive a benefit season from Yorkshire, but was released from the county the season before.
This came as a surprise to Leadbeater, who had agreed to become the Second XI captain earlier in the season. This responsibility then went to Colin Johnson.
Leadbeater was released from the county, finding out whilst in the local golf club
Leadbeater was the third umpire in two Test matches, in 1993 and 2000. He umpired one further ODI – seventeen years later at Trent Bridge in 2000. He retired from first-class umpiring at the mandatory age of 65 in September 2008, his final game being the match between his beloved Yorkshire and Somerset at North Marine Road, Scarborough.