A 7-year-old New Jersey boy spent three years growing his hair long, defying teachers at his Catholic prep school and withstanding bullying from other boys — just so he could donate it to kids with cancer.

Kaleb Ramos violated a policy against boys with long hair at St. Philip in Clifton, NJ, mom Sovedia Cespedes told The Post.

“They gave me anxiety even though I told them he’s growing his hair for a special reason,” she said.

She says she pulled her son out of school over that policy and other issues.

On Tuesday, the boy’s persistence paid off, as a stylist chopped Kaleb’s 24-inch locks down to 10.

The school principal did not return a call requesting comment.