Walker, a left-handed batsman, spent 17 seasons at Kent having made his debut in 1992.
He was particularly highly regarded during his younger days, captaining England Under-19s in 1993 and hitting an unbeaten 275 against Somerset three years later - the highest score by a Kent player at Canterbury.
However, Walker failed to progress as many had expected and it was not until 2001 that he rediscovered his best form on a consistent basis, averaging above 40 as Kent finished third in the County Championship.
He passed 1,000 runs for the season in 2003, and his tally of 1,234 championship runs at an average of 56 won him the player of the year award the following summer.
Named one-day captain after David Fulton stood down midway through 2005, Walker topped the Kent run-scoring charts once more in 2006, finishing the campaign with 1,419 at 61.
He helped Kent win the Twenty20 Cup in 2007, but found first-team opportunities hard to come by in 2008 - his benefit year - and joined Essex on a two-year deal after being released at the end of the season.
Walker became an important part of Essex’s batting line-up in all formats and, in December 2011, he was handed the assistant first-team coach role at Chelmsford after Graham Gooch relinquished his position to work with England on a full-time basis.