There were 7 teams in the 1978 ACTAFL Competition, Ainslie, ANU, Belconnen, Eastlake, Manuka, Queanbeyan and West Canberra.
Ainslie signed former St Kilda player Kevin Neale as the new playing coach on a two year contract. Neale played 256 games for St Kilda and kicked over 300 goals.
Ainslie finished on top of the table after the home and away games with 14 wins and 4 losses ahead of Eastlake on percentage.
Ainslie defeated Eastlake in the Second Semi-Final to go through to the Grand Final.
- Final score: Ainslie 11.15-81 def Eastlake 10.11-71
- Goal kickers for Ainslie: J Brock 4, K Neale 2, R Davey 2, M Smith 1, W Batchelor 1, D Bellchambers 1
- Best: B Holford, J Brock, V O’Donnell, N Bristow, D Bellchambers, B Hannam
After leading in the Grand Final by 27 points at half time Ainslie were overrun by Eastlake in the second half to lose by 24 points before a record crowd of 9,500 at Manuka Oval.
- Final score: Ainslie 16.17-113 def by Eastlake 19.23-137
- Goal kickers for Ainslie: J Brock 3, R Davey 3, D Bellchambers 3, M Smith 3, K Neale 1, W Batchelor, B Johnston 1, P Neeson 1
- Best: M Smith, D Bellchambers, N Bristow, B Shanley, A Smith
Ron Davey was second in the First Grade leading goal-kicker with 69 goals.