An ex-Eton College teacher accused of assaulting pupils helped "boys flourish in their careers", a court heard.
Matthew Mowbray, 49, is accused of entering boys' rooms at night, under the guise of discussing schoolwork, to sexually touch them.
He denies nine counts of sexual activity with a child, involving four boys and one girl.
Ex-pupils told the jury at Reading Crown Court Mr Mowbray was dedicated to his job and was a "parental figure".
Former student Arthur Croft said the geography teacher had put an end to some traditions for new students, including one which involved them being made to dance in front of others while being shouted at.
"He made a decision that it should be outlawed on the basis it encouraged bullying, he put a stop to it," Mr Croft said.
He said of Mr Mowbray: "He took his duties seriously.
"He was entirely dedicated, basically helping boys flourish in their careers."
Another former student, Alexander Kintzer, told the jury Mr Mowbray was a "parental figure" to whom he could talk about personal issues.
He said Mr Mowbray would check on boys at night to "enforce bed time" and ensure "academically we were comfortable and on track".
The teacher, who was dismissed from the school following his arrest, will not be giving evidence in his trial, defence barrister Sallie Bennett-Jenkins QC said.
Jurors previously heard that Mr Mowbray, of Locks Heath, Southampton, had made pupils "freeze" as he allegedly fondled them in the dark during night-time visits to their bedrooms at the boarding school near Windsor, Berkshire.
He has admitted six counts of making indecent images of children and one count of voyeurism, jurors heard.
The trial continues.