Khawlah and her 10-year-old brother, Mohammed, ran away from the man to join a group of children so they would not be alone with him, but became separated at the traffic lights.
The man apparently returned a short time later and continued to cut her hijab from behind.
When they got to school they found that her hijab had a 30cm cut in at from the bottom.
Toronto police say no physical injuries were reported in the incident and investigators are actively looking for a suspect.
The girl, 11, described the suspect as an Asian male in his 20s with a medium build.
The girl's mother said she was angry someone would target a child, but was relieved her daughter was not physically harmed.
Bird said the school board is offering support to the affected student and her family.
Ontario Premier Kathleen Wynne and Toronto Mayor John Tory also released statements condemning the attack.
"He just smiled and ran away", says Khawlah. And we'll be working closely with police to offer any assistance that we can, ' Ryan Bird, a school board spokesperson, told CNN partner CBC.
At the time of the attack, he was wearing a black, hooded sweatshirt, black trousers, brown gloves, and had prescription glasses with black frames on his face, police said.
Prime Minister Justin Trudeau condemned the attack, along with other Canadian politicians.
'My heart goes out to Khawlah Noman following this morning's cowardly attack on her in Toronto, ' he wrote. "I'm a kid", the girl said to her attacker.
Toronto police are investigating after a girl was attacked by a man wielding scissors in Scarborough Friday. "Intolerance and hate of any kind, including islamophobia, has no place in our city, our province, or our country".
"We must stand firm in our support of this young girl who was assaulted simply for wearing a hijab", she said.
"This is a cowardly act of hatred". I am so proud to be a Canadian, and I want to give (the attacker) the same message'.