Kevin Joseph Aje was born on 25 April 1934 in Amper District in Pankshin Division (now Kanke Local Government Area of Plateau state).
Aje studied Philosophy and Theology at Saints Peter and Paul Major Seminary, Bodija, Ibadan.
He was ordained to the episcopate by Pope John Paul II on 6 January 1983 in Rome to succeed Bishop Michael James Dempsey OP.
[5] Aje encountered difficulties in trying to build new churches in a predominantly Muslim state,[6] but was enthusiastic about Pope John Paul II's desire for the Legion of Christ to make a special effort in Europe to recover the faith that had done so much good elsewhere.
[7] Throughout his tenure he appealed without success to the Sokoto and Zamfara state governments for a land grant that would allow the Catholic Church to construct a hospital.