Thomas Harran, who taught at Hereford technology school from September 2002 to October 2004, is said to have told one pupil: "I am surprised you can count to six."
Parents and pupils complained and almost an entire class signed a petition claiming that he had insulted them.
Jim Cunningham, the former head of the school, said Mr Harran's class was out of control. Five teachers observed his lessons and one said children were too upset to attend and played truant to escape being taught by him.
Mr Cunningham said the college was rated as challenging by the Department for Education and Skills and had 1,100 pupils from one of the most disadvantaged areas in England.
He said Mr Harran had been incapable of reaching the required standard, failing to react to advice from others or the instigation of formal capability proceedures. "Mr Harran said he had very high expectations of pupils and when pupils were unable to meet those... he felt they were against him," Mr Cunningham said. "Their behaviour was a direct response to the way they were treated by Mr Harran."
Mr Harran resigned in October 2004 but Mr Cunningham said he would have been dismissed anyway.
Mr Harran is charged with failing to establish a relationship with pupils conducive to effective learning.
Andrew Allard, head of maths, said the feedback from other staff about his lessons was negative. He regularly had to intervene in Mr Harran's lessons and had warned him about breaking school policy by keeping his whole class behind for detention after school and at lunchtime.
"I can't stress too strongly I felt that pupils should not be taught by him any longer," he said.
The hearing was adjourned.