[8] In 2002–04, Colonel Hayat was posted by the Ministry of Defence on a diplomatic assignment, serving as a military and air attaché at the High Commission of Pakistan in London, United Kingdom.

[16][17] In 2013, Lieutenant-General Hayat was elevated as a field commander of the XXXI Corps, stationed in Bahawalpur but this appointment remained short-lived.

[23] Initially, the race for the appointment for the army chief was rumored to be between Lt-Gen. Hayat and Lt-Gen. Javed Ramday who was close to the first family.

[27][28][29] In March 2019, at a conference organised by the Pakistan Institute for Conflict and Security Studies (PICSS),[30] in collaboration with the Institute of Business Administration (IBA), Center for Entrepreneurial Development (CED), Karachi, he categorically underlined the historical foundation of Pakistan in Mehrgarh, and the mistakes made by United States in Afghanistan, in his key note address.

His younger brother, Lt-Gen. Omar Mahmood Hayat, had briefly served as chairman of the Pakistan Ordnance Factories (POF) before being transferred and posted at the National Disaster Management Authority (NDMA)[32] while his youngest sibling, Ahmad Mahmood Hayat served as a Director General in the Inter-Services Intelligence (ISI).