John Hamey was head of Sydney's Moriah College from 2011 until 2018 and appeared at the royal commission into anti-Semitism on Thursday.
He shared frequent incidents of Jewish students being targeted by pupils from other schools and members of the public.
When visiting other schools, students would throw coins in front of them to see whether they would pick them up "because they were Jewish", the inquiry heard.
"There were often taunts that invoked the gas chamber and statements along the lines of 'Hitler should have finished the job'," Mr Hamey said.
Students were being worn down by frequent traumatic incidents, which got brushed off as "just something that they had to deal with and they had to get on with", the former principal said.
"It was not necessarily something they would report because they would say, 'well, nothing would happen', or there'd be no serious outcome or consequence for the perpetrators of that anti-Semitism."
Outside of Jewish institutions, Mr Hamey said most teachers weren't well informed about Jewish cultural life or equipped to identify anti-Semitism.
"They really lack the language," he said.
"Because it's too politically contentious, they will minimise those actions and just deal with them as ... one-off incidences or just a simple form of bullying."
The first witness to front the inquiry on Thursday was a mother sharing her son's experience with anti-Semitism at school.
She said the school made efforts to ensure the safety of her son and spoke to the offending students.
The witness also recalled the positive impact of speakers presenting to parts of the school to explain the collective trauma of the Holocaust for the Jewish community.
But she said education needed to apply to teachers as well, referring to one occasion where her son removed himself from a classroom when a teacher wore a "Free Palestine" badge featuring a fist of resistance.Â
"Words and symbols can mean different things to different people and, to him, that badge made him feel very unsafe in the classroom," the mother said.
"Even a badge promoting peace between Israel or Palestine, from my perspective, shouldn't be worn into a classroom. It's not the place for it."
The special envoy to combat anti-Semitism will make another appearance in the royal commission's hot seat later on Thursday.
Jillian Segal, who was appointed to the role by the federal government in 2024, will testify as the commission focuses on anti-Semitism education and training, and its effectiveness.
In a report released in 2025, the special envoy called for Holocaust and anti-Semitism education to be put in place in national and state school curriculums.
The education plans would be co-ordinated with government, independent and Catholic school systems.
The plan also called for anti-Semitism education for teachers and public officials to ensure a foundational and practical understanding of the issue.
