A landmark High Court declaration will compel education chiefs to encourage and support the integrated sector in Northern Ireland, campaigners claimed.
As its special status under legislation was confirmed, hopes were also raised that a school behind the challenge can now undergo significant expansion.
Drumragh Integrated College in Omagh issued judicial review proceedings after the Department of Education initially refused a proposal in 2012 to increase its intake from 580 to 750 pupils.
Even though Education Minister John O'Dowd announced last year he would rethink the decision, lawyers for the school pressed ahead with the action.
They argued the department was failing to support integrated education, the legal duty of his department under Article 64 of the 1989 Education Reform Order and the Good Friday Agreement.
Last month Mr Justice Treacy backed its case, stating that the department needs to be alive to the Article 64 duty at strategic and all other levels.
One of the issues in contention had been whether the legislation could be applied to any school that had both Protestant and Catholic pupils, rather than specifically to an integrated school.
But a new declaration issued yesterday by the judge went further, confirming the judicial review was granted and setting out the sector's status.
It said: "The court declares that Article 64 of the Education Reform (Northern Ireland) Order 1989 applies only to integrated education as a standalone concept within the confines of part VI of the 1989 Order."
Counsel for the department confirmed that guidance issued will be reviewed in light of the judgment.
Outside the court Tina Merron, chief executive of the Integrated Education Fund, expressed delight at the outcome.
She said: "The department now has to recognise its duty to encourage and facilitate integrated education; it has to do something positive.
"The normal status quo has to change, and we think the department will have to ask parents what they want."
Nigel Frith, the principal at Drumragh College, said the school can now remind the department of its obligation in any future proposals.
"I trust the minister will now look favourably on our development," he said.
"I would hope he will find it difficult to turn us down and indeed that he will fulfil the 1989 Order by helping the school to expand."