"What a way to treat somebody who's doing you a favor," said Smith.
Smith, a parent and friend of MyGrant, told Channel 2's Carl Willis the educator had to slip away from security to avoid further humiliation.
"He snuck out the back door. He saw what was going on," she said.
The Parent Teacher Student Association (PTSA) told Willis the most concerning part of this dismissal was the removal of the school's entire administrative team.
They've all been reassigned to other schools.
Students said they were stunned.
"We are setting up a walkout for Wednesday," said student Carlin Smith. "People are just outraged."
Channel 2 Action news asked Atlanta Public Schools spokesman Stephen Alford why the move happened so suddenly and without warning.
"We understand change is not easy for anyone," Alford said over the phone. "We want what's best for our students."
Still, parents including Rick Calcagno, who has two students in the school, said, "That was just poor judgment and I think unprofessional and uncalled for, given what he's done for the school."
Calgano echoed the sentiments many parents shared about MyGrant, saying that he helped turn the school around, which led to parents enrolling children in the APS school rather than private institutions.
MyGrant said Saturday that he has evidence that the move was politically motivated and stems from a claim that two of his recommended hires were racists.
His supporters said they would plan a peaceful demonstration at the school Tuesday.
"What we would like is the current administrative staff reinstated for the transition period," said Smith.
APS Superintendent Erroll B. Davis Jr. plans to meet with parents on the campus to talk about leadership transition and the new direction of the school Oct. 9 at 6 p.m.