Mustafa joined Hafeez Pirzada Law Associates in 2007 where he acted as an Associate for over nine years along with practicing independently before becoming a Partner at the Firm. He has extensive experience both in litigation before various courts and tribunals and in providing general corporate and legal advisory services. Before returning to Pakistan in 2007, Mustafa also had experience of practicing in the United Kingdom.

Mustafa regularly appears before the High Courts of Islamabad, Lahore, Peshawar and Balochistan in a variety of cases and covering most of the services that the Firm provides including inter alia constitutional, tax, oil & gas, mining, power generation, public sector contracts and procurement, election laws, general civil matters, labour and service matters, contractual disputes, environmental laws, anti-dumping, defamation, white collar crime and other matters. Besides appearing before the High Courts of Pakistan, Mustafa also appears before the Election Commission of Pakistan, the National Tariff Commission, the Competition Commission of Pakistan, the appellate bench of the Securities & Exchange Commission of Pakistan and the National Electric Power Regulatory Authority.

Mustafa is regularly engaged by both local and foreign companies operating in Pakistan for the provision of general corporate legal advice on company law, regulatory compliance, contractual, constitutional, employment and labour matters, rent and tenancy issues, and other day to day legal matters. In addition to the foregoing, Mustafa regularly provides advice to government and multilateral institutions. He also provides advice to political parties and senior politicians, as a part of which he was inter alia involved in the process of drafting the Constitutional (Eighteenth Amendment) Act, 2010 with the Joint Parliamentary Committee on Constitutional Reform.