Another product of the Crystal Palace academy, midfielder Williams has progressed through the youth ranks and signed his first professional contract with the club in April 2010. The Welshman has already represented his country at a number of levels including the under 21s and is rated highly by the Crystal Palace management.
Williams made his debut in the 2-1 win over Coventry city a Selhurst park, making his full debut a week later against Crawley Town in the Carling Cup, claiming an assist in the process. His impressive form for the academy side saw him named in the Wales under 21 squad at just 16 years old. Williams also got assists against Middlesbrough before breaking his leg in action for Wales U21s.
Jonny would have to wait until March to get back to action against Hull and finished the season with 14 appearances.The high regard Williams is held in was shown on 10th May 2012,as the Welshman signed a five year contract with the club.