Duncan MacMillan High hosts grades primary–12, as well as a pre-primary program and teaches 249 students.

It has the largest geographical area for bussing in the Halifax Regional School Board.

Although DMHS is small in student population, it does provide the courses necessary for any post-secondary program.

In addition to the services provided directly by the Halifax Regional School Board, DMHS is also provided service by the Nova Scotia Health Authority via the school's Youth Health Centre.

[7] In December 2013, the HRSB began a plan that would eventually see all of the DMHS feeder schools closed, the present DMHS building vacated and possibly demolished, and in their place will be a single new school serving grades primary through 12 in Sheet Harbour.

[8] SHCS was closed in 2017 after sixty years of operation to further the construction, and the students were relocated to DMHS and will be until the opening of the new school.