Despite winning the Allianz League Division One title in March 2024 under Gallagher’s successor Mickey Harte, Derry have struggled since his departure.
They surrendered their Ulster title with an emphatic defeat by Donegal in last year’s quarter-finals and this season were relegated to the league’s second tier.
It is a stark contrast to the team that won a pair of provincial titles in 2022-23.
McKinless, who also pointed to the influence of assistant coaches like Ciaran Meenagh, felt the environment during the period ensured success.
“We were all singing off the same hymn sheet, we all had the same goals and we were working towards that every day,” he said.
“The credit to the management team was the environment they created for the players to excel in. They pushed us to the limits we never thought were possible.
“On the pitch and nearly more off the pitch, how we see the game and how we understand it was probably a bigger element than most. We had teams beaten before we’d play them.”
Looking to rebound from relegation, Derry begin the Ulster Championship with a trip to Ballybofey to face Donegal in the preliminary round on Sunday.
They will travel as considerable underdogs and McKinless, who will miss the campaign with a cruciate ligament injury, said the change in status has been difficult for the players.
“We had massive aspirations to go and do special things – when it comes crashing down, it’s hard to put into words, it’s hard to take,” he added.
“You go from being a top three or four team in the country, to being down the pecking order. For that group, it’s hard to take.”
You can listen to the GAA Social with Gareth McKinless on BBC Sounds now
