Nkusi served as literature and language lecturer at the University of Rwanda for 24 years between the years of 1976 and 2000, before he was appointed as the Minister of Land and Environment for three years.

Nkusi was later appointed as the Information Minister before he served as the vice-rector in charge of academics at the Institute of Agriculture, Technology, and Education of Kibungo (INATEK).

He attended his primary school education in Huye district and High school in Nyanza after which he enrolled at the University of Rwanda, where he studied literature.

To his students, Nkusi had established himself as a lecturer who was committed to doing everything possible to follow up on the problems affecting quality education at higher institutions of learning.

"I cannot forget his fight for the school of journalism and mass communication to exist" one of his students, Flavia Salafina, an Information, Education and Communication specialist at the Ministry of Education said.