[5][6][7] Born with pneumonia and suffering from lung problems when young, Deer worked hard to build his physical strength.
He also got a teaching certificate and taught for a time at a high school in Kahnawake, but decided to pursue another field.
Deer next worked at the library of the Union of British Columbia Indian Chiefs, where he adapted his system to classify its holdings.
He designed his work for flexibility to reflect local communities and their small, specialized collections.
[10] Deer returned to Kahnawake where he worked on classifying and organizing materials at its Cultural Centre and at the Mohawk Nation Office.
For instance, Keltie McCall and Gene Joseph, also working for the Union of BC Indian Chiefs Library, revised the Brian Deer Classification System for local use.
[4] When working later for the University of British Columbia, Vancouver, Joseph adapted the BDC-BC from 1984-1986 to classify the collection of the Indigenous Teacher Education Program (NITEP) there.
[1] Deer's work has had increasingly wide influence in the early 21st century on the practice of librarianship and on the theory of knowledge organization, especially as it relates to Indigenous peoples.
[9] In 2014 the Union of British Columbia Indian Chiefs Resource Centre released a new revision of the BDC-BC System.
The Aanischaaukamikw Cree Culture Institute in Oujé-Bougoumou, Quebec also uses an updated version of the BDC system.