Michael Mousdale has left his job as principal solicitor at Bristol City Council to join Eversheds of Leeds.
In his first private practice post he will be in charge of the firm's public sector unit, which will involve advising local authorities on CCT, PFI and TUPE matters.
His work will involve advising some private clients but the firm's public sector unit will not act for private sector companies competing against its local authority clients on individual CCT contracts.
Before joining Bristol City Council in 1990, Mousdale worked at Woodspring council before it became a part of North Somerset.
He said: "There are exciting opportunities at Eversheds and it will give me a chance to diversify my client base."