Padraig O'Shea, the former principal of St Joseph's College in Borrisoleigh, Tipperary, has spoken publicly for the first time since the Children's Ombudsman ruled that the school had discriminated against the 16-year-old.
He insisted there "must be standards of morality in every school and that is the wish of 99pc of parents".
Ombudsman Emily Logan reported that the teenager applied to St Joseph's when she was pregnant, and again after giving birth, but was refused entry both times in 2009 and 2010.
In an exclusive interview with the Irish Independent, Mr O'Shea said Ms Logan and various politicians "gravely misjudged the moral integrity of the Irish people".
Now the school manager -- who says he has received "universal support" for his stance -- has claimed Ms Logan had refused to debate the issue on television with him.
"There is nothing to apologise for. I wish her every success in life," Mr O'Shea said. "Parents appreciate discipline in a school. It is my duty to ensure that parents who repose confidence in me are duly rewarded, and my student body and my staff are people of the highest integrity and we shall retain our reputation in all respects. Simple as that."
The former principal retired in 2009 but continues to work as school manager at the privately owned Catholic school, which has more than 300 male and female students.
Ms Logan's report on the matter said that the teenager, who was not named, had attended two schools and was then refused entrance to St Joseph's both before and after giving birth in 2010.
However, Mr O'Shea disputes her claims.
"She was in three schools before she sought entry here -- the ombudswoman said she was in two schools. Now if you were principal, wouldn't that lead to questions?" he asked.
"She (Ms Logan) says she came a second time -- I have no recollection of her coming a second time," he said. "There was also a statement made that students and teachers asked me to take her in. No student and no teacher ever asked me to take her in. Enrollments are done during the month of August when neither students nor teachers are present anyway."
In the complaint to the Children's Ombudsman, the teenager said she felt "hurt and discriminated against" after being refused admission to the school.
"I felt ashamed and embarrassed that someone could make me feel this way for being a single young mother," she said.
Her mother said the school's actions caused immeasurable damage to the girl's self-esteem, and that they felt stigmatised and slighted as a family.
Support
But Mr O'Shea said if the same scenario arose again, he would still adopt the same stance and refuse a pregnant teenager entry.
And he said he had received the support of people in the locality.
"It took us an hour to get home from Mass the first day -- the church is only up the road. They were holding us up and chatting to us in shops and all. They were saying congratulations," he said.
"I got 92 letters in less than three weeks and several phone calls from past pupils and parents," he added. "Teachers from other schools supported me. There was universal support. The ombudswoman gave me tremendous publicity -- throughout Munster especially -- and I thank her for it."
North Tipperary TD Alan Kelly and Ms Logan called on him to apologise to the teenage mother last April.
However, Mr O'Shea said: "They gravely misjudged the moral integrity of the Irish people, particularly parents. There must be standards of morality in every school and that is the wish of 99pc of parents."