When Sudan gained independence from the Condominium colonial rule in 1956, Ukel was attending the government Intermediate School in the Equatorian town of Maridi, where he graduated in 1958.
When the Anyanya rebellion escalated in Equatoria, Ukel moved to Northern Sudan, where he first worked as a schoolteacher in the Gezira area and then continued his studies at the University of Khartoum.
When the Addis Ababa Agreement of 1972 ended the Anyanya rebellion and granted Southern Sudan autonomy, Ukel moved back to Bahr el Ghazal, where he taught English at Rumbek Secondary School.
[3] When Alier lost this office in October 1981, Ukel became the secretary for the publicity committee of the “Council for the Unity of the Southern Sudan” (CUSS) which advocated against the redivision of the South.
In its campaign for the 2010 general elections, USAP defined as one of its main goals “unity in diversity” as opposed to separation, which it emphasized by the choice of Khartoum as its headquarters.
After the independence of South Sudan in July 2011, Ukel was appointed Minister of General Education and served in this office until President Salva Kiir dismissed the whole cabinet in August 2013.
[14] On 12 September 2018, the Revitalized Agreement on the Resolution of the Conflict in the Republic of South Sudan (R-ARCSS) was signed in Addis, Ukel was one of the six signatories representing the Umbrella Coalition of Political Parties.