The 35-year-old joined the club in the summer as part of Paul Sheerin’s backroom team and was previously linked with a move back to his hometown team Carlisle United as manager.
Cumbrian born Grainger was listed as the second favourite for the job by most bookmakers, but the Falkirk Herald can reveal he will not be in the running.
The ex-Workington boss and Hearts legend said: “I won’t be looking to take the job at all.
We need to forget about Saturday's defeat quickly, says Falkirk midfielder Nesbitt
Diamonds shine as ten-man Falkirk falter in heavy defeat
Boxing: Sparta's Thomas O'Reilly earns Scotland call
Pace boss Smith sees defeat as only a blip
'Things did conspire against us' - Boss John McGlynn on Falkirk's second-half display
“I have got aspirations to work as a manager again, but right now I have no interest in this role. When the new regime comes in my position will be reviewed then.
“The board asked me to take the time for the interim period and I was happy to do so. The group of players we have here are all brilliant lads to work with on the training pitch.”
Grainger admitted the departure of Sheerin came as a complete shock to him, and that the dressing room in the aftermath was the ‘flattest’ he’s seen in his 20-odd year spell in the game.
“I don’t think I’ve ever seen a dressing room as flat and emotionally drained. Everyone was disappointed to see the manager leave and that is a testament to the respect Paul had from the group.
“There has been comments and what has happened behind closed doors and they will stay behind closed doors.”
Falkirk’s 6-0 loss to Queen’s Park was one the worst in the club’s 144 year history and the interim coach acknowledged the supporters' anger.
He said: “It was unacceptable to lose a match like that against a team you are wanting to challenge so I understand why the fans felt the way they did.
“As I mentioned things were said and some home truths were told because you can’t come away from a result like that and not feel guilt and anger.
“From my own point of view I was frustrated because I felt myself and Paul could turn it around and that we had put good foundations in place.”
On Saturday the league leaders Cove Rangers, led by ex-Bairns boss Paul Hartley are the visitors with Falkirk stuck in fifth spot outside the promotion playoff spots.
“The crowd will expect a reaction and we have to give them that,” said Grainger. “It will be a tough match but picking up three points is still the goal for us.
“The players need to believe in themselves and show the ability I know they have on the park.
“I’ve only had them for two sessions so there won’t be wholesale changes, I truly believed in what Paul wanted to do and how he wanted the team to play.”
The club are well underway with the search for a new head coach and are hoping to make a swift appointment ahead of a busy December period and the upcoming January transfer window.