Born 1930, Ezeilo took his PhD at Cambridge in 1958 under M. L. Cartwright (Chike Obi's supervisor), with a thesis on boundedness and stability of solutions of third-order nonlinear ODEs. He returned to UCI (later UI) briefly, then moved to the University of Nigeria, Nsukka in 1965, where — interrupted only by the Biafran war — he built UNN's mathematics department.
The published corpus is roughly seventy papers across *Proceedings of the Cambridge Philosophical Society*, the *Journal of the London Mathematical Society*, the *Annali di Matematica Pura ed Applicata*, and *Acta Mathematica Hungarica*. The central technique is the construction of complete Lyapunov functions for higher-order nonlinear ODEs to establish global asymptotic stability of equilibria.
Ezeilo was the first Vice-Chancellor of the University of Nigeria, Nsukka after the civil war (1971–74), later VC of Bayero University, Kano (1978–84), and founding Director of the National Mathematical Centre, Abuja — the institution that, in the 1990s and 2000s, became the principal venue for sustained postgraduate mathematics training in Nigeria.
He died in 2013. The continuity of Nigerian higher-order differential-equations research from his work to the present — including significant continuation by Tunde Afuwape (UI) and Anthony Tiryaki (Turkey) — is one of the very few completely intact Nigerian mathematical lineages.