Himayat Ullah Khan studied in Aitchison College, Lahore, Edwardes College Peshawar and obtained Masters in Economics from the University of Peshawar. In 1979, he joined the Pakistan Audit & Accounts Service. In 2010, he was promoted to Basic Pay Scale-22 and inducted into the Secretariat Group. He got extensive training from the Institute of Development Studies University of Sussex UK; International Agriculture Centre, Wageningen, The Netherlands; and the Kennedy School of Government, Harvard University, USA. During his professional career of more than 42 years, he worked at senior policy formulation, regulatory and operational levels with the Federal and Provincial Governments. Strategic planning, managing organizational change, leading large teams, working with public and private sectors and development partners are major highlights of his diverse experience.  

He has in-depth knowledge and experience of government finance, accounts and statutory audits and has served as Accountant General. Khyber Pakhtunkhwa. In the Federal Government, he worked as Joint Secretary to the Federal Cabinet, Council of Common Interest and Secretaries Committee. While serving in the Ministry of Commerce, he worked as Chief Negotiator and successfully negotiated the Afghanistan Pakistan Transit Trade Agreement (APTTA), 2010. In 2013, he held the portfolio of Special Secretary to the President of Pakistan.

He remained associated with the power sector for more than 20 years and developed a deep understanding of the issues and challenges of the sector in Pakistan. He served as Secretary Water and Power Development Authority (WAPDA) from 1998 to 2003. He also worked as the National Coordinator for Water & Hydropower Development Program-Vision 2015. As Additional Secretary Economic Affairs Division he successfully negotiated $840 million loan with the World Bank for the 1410 MW Tarbela-IV Hydro Power Project. In 2012-13, he served as Special Secretary Ministry of Water & Power. He also served as Member, National Electric Power Regulatory Authority (NEPRA) in 2014-18. In 2018, he was appointed Advisor to the Chief Minister Khyber Pakhtunkhwa for Energy & Power and held the portfolio till 2021. In 2023, he worked as Advisor to the Government of Khyber Pakhtunkhwa and looked after the Finance, Energy and Power Departments.  He has served as a member on the Board of Directors, Sui Northern Gas Pipelines Limited (SNGPL).

He is a committed environmentalist. In 2002-08, he contributed as Member Board of Governors, World Wide Fund for Nature (WWF)-Pakistan. In 1997-98 he was Vice Chairman, Executive Committee of Pakistan National Council of IUCN Members. He is regular visiting faculty of National Institute of Management, Karachi and Peshawar. He also remained on the Board of Governors, Fazl-e-Haq College, Mardan. He is currently holding the position of Chairman, Board of Governors Peshawar Electric Supply Company (PESCO), Hazara Electric Supply Company (HazESCO), Tribal Area Electric Supply Company (TESCO) and the Khyber Pakhtunkhwa Oil and Gas Company Limited (KPOGCL). He also sits on the Boards of Sahibzada Abdul Qayyum Trust and Frontier Association for Mentally Handicapped.