Under Wachuku's leadership at the United Nations, both the Nigerian Army and the Nigerian Police Force made their début with the UN peacekeeping effort. During his time at the United Nations, Nigeria's Major-General Johnson Aguiyi-Ironsi was appointed Commander of the United Nations Peacekeeping Force in the Congo. Also, the first Nigerian Permanent Secretary, Mr. Francis Nwokedi, was retained by the United Nations to help in the reorganisation of the Civil Service in the Congo. Wachuku also secured the appointment of the first African Under-Secretary-General of the United Nations – Nigeria's Godfrey K. J. Amachree – who became UN Under Secretary-General for Trusteeship and Non-Self-Governing Territories.