Onen is a Catholic priest who served as the second curate of Holy Rosary ParishCatholic Church. He was a priest for eight years before joining active politics. The Bishop of his Gulu DioceseJohn Baptist Odama issued him two warning letters to desist from active politics in accordance with the Canon Law but Onen reportedly ignored warnings. The Bishop then issued a decree of suspension ‘a divinis’ as prescribed by Canon Law 285. Onen went into politics as an independent candidate and secured a nomination to run for the Gulu East constituency on 15 October 2020. Onen campaign focused on unity and improvement of living standard. He won the election after beating his challengers including the incumbent MP.