[2] Onek Hilary was born on 5 May 1948, the second born to Samson Okello Otto, son of Rwot Damwoy of Pakala Clan in Palabek Gem and Mrs. Jera Ayoo, daughter of Rwot Onyanga, the Paramount Chief of Palabek, one of the six chieftaincies of Lamwo County.

Mze Samson Okello Otto was serving in the King's African Rifles (KAR) in Kenya during 1946 when he married Mama Ayoo.

Following his MSc studies, he completed a one-year fellowship at the Moscow Institute of Civil Engineering in Hydropower Dams & Hydro-technical Structures, from 1979 until 1980.

Hilary Onek also holds a Postgraduate Certificate in Investment Appraisal and Management, from Harvard University, in Cambridge, Massachusetts, United States, obtained in 1994.

He worked as an Assistant (pupil) Site Engineer, Nurek 305m Hydropower Dam Construction, Tajikistan (USSR), from May until August 1977.

Between May and August 1978, he worked as an Assistant (pupil) Site Engineer, 280m Inguri Hydropower Concrete Arc-Dam Construction, in the Republic of Georgia in the Soviet Union.

His findings were presented at Energy Workshops sponsored by the National Research Council and other industry groups.

During his tenure at the helm of NWSC, water and sewerage services, which were limited to Kampala, Jinja and Entebbe, were expanded to cover other towns including Mbale, Tororo, Masaka, Mbarara, Kasese, Fort Portal, Gulu, and Lira.

Between 1998 and 2001, he worked as an independent, private consultant at a company called EOM Services Limited, offering services with other consultancy groups, in the areas of Human Resources Management, Investment Appraisals and Management, Water Supply and Structural Engineering.

He was appointed Minister for Agriculture, Animal Industry and Fisheries in June 2006, serving in that capacity until February 2009.

[7] On 16 February 2009 Hilary Onek was appointed Minister of Energy and Mineral Resources, a position he worked in until May 2011.