Head teacher Matthew Tate, of Hartsdown Academy in Margate, has been compared to the Gestapo by parents angry that their children were sent home.
The majority of students were sent home because of not having appropriate uniform.
Mr Tate has a reputation for turning around failing schools and has defended his strict uniform rules.
He told the Daily Mail on the second day of the school term that "I think it's nonsense when people think caring for children is allowing them to do whatever they want and to have no expectations for them.
"I'm a parent. I expect great things of my children and I don't allow them to do whatever they want. Because I care and because I love them.
"I think all schools need to have high expectations of their children.
"What is needed is saying, 'Actually, this is what we expect, this is what we believe in and following through with it'.
"If we as educators and schools did that, we would have much better schools."
The headmaster has a degree in theology and led the first church-led free school, involving 29 churches from different denominations.
Matthew Tate also works at his local church and Christian centre.
Speaking to the paper at the time of his appointment, the trust's executive head teacher, Paul Luxmoore, said Mr Tate was both "compassionate and tough."
He added that the school supported Mr Tate in his uniform policy.
Premier has contacted Hartsdown Academy for comment and is awaiting a response.