Mahmood replaces Croydon North MP Steve Reed, who becomes shadow secretary of state for the environment, food and rural affairs.
She has previously served on the Public Accounts Committee, and was shadow chief secretary to the Treasury for four months in 2015, in acting leader Harriet Harman’s shadow cabinet, as well as occupying three shadow ministerial roles (Treasury, higher education and prisons) in Ed Miliband’s team.
Mahmood grew up in Birmingham and studied law at Lincoln College, Oxford, later specialising in professional indemnity litigation as an employed barrister.
Law Society president Lubna Shuja said: ‘Her background in the legal sector stands her in good stead to grapple with the many complex and urgent issues we face across the justice system. We look forward to discussing these further with her very soon.’