Abronhill High School is facing closure under plans by North Lanarkshire Council to merge it with nearby Cumbernauld High.
McCredie, whose wife used to teach at the school, said: "I was interested in the campaign, particularly as Gregory's Girl was filmed there.
"I feel that with a new town like Cumbernauld, pulling everything down means effectively killing history and in particular the history of Gregory's Girl, which is one the best Scottish movies of all time.
"The pupils in this situation are going to lose a school with two schools pushed together – that alone will be one big change – but moving to a new build a few years later will mean yet another move.
"That's something I don't agree with, I think it's making kids do things twice and it sounds like a rush job to me."
A consultation into the proposed package of savings, which includes the closure of Abronhill, closed last week.
The council is proposing to close the school from August 2013, with pupils transferring to Cumbernauld High, which itself may be replaced at a later date by a new-build school.
It is understood the Abronhill closure will save the council more than £1 million a year.