Brennan's transfer from Sligo to Donegal proved controversial, generating much media coverage and opposition from rival clubs.
[5][6] The dispute led to the final of the 2002 Donegal Senior Football Championship not being played until 2003.
[7] He had stopped playing for his club by the time it won the 2014 Donegal Senior Football Championship.
[8] He jointly managed the St Eunan's senior footballers with Barry Meehan in 2017.
[10] Downings appointed him as team trainer ahead of the 2020 season.