John Walker began his career in 1985 as a junior clerk at 39 Essex Street, moving to Brick Court Chambers in 1987 and to Quadrant Chambers in 1989. He qualified as a member of the Institute of Barristers' Clerks in 1992.

John was appointed to the position of Practice Manager at Quadrant Chambers in 1999 and assists the senior clerking team with the management and maintenance of counsel's diaries. He liaises with instructing solicitors on new and existing instructions and deals with the management and allocation of court and arbitration commitments. He also deals with the agreeing and processing counsel's fees.