Bishop Okpaleke becomes the fifth Cardinal from Nigeria. Others before him are Dominic Ekandem, Francis Arinze, Anthony Okogie and John Onaiyekan.
He is among the 21 new Cardinals Pope Francis announced on 29 May.
In a congratulatory message by his media aide, Buhari commended the Pope for finding a capable Nigerian in the person of Bishop Okpaleke to be one of the two nominees from the African continent.
He also congratulated the Nigerian Christian Community on this choice, describing the Cardinal-designate as ably qualified, and that having him in that position would benefit the country.
The president also commended the commitment of the Catholic Church to unity, peace and progress of the Nigerian state.
He also highlighted the effort of the Church in combating the COVID-19 pandemic as well as its support and commitment in favour of the poor and most vulnerable members of the society.