Thornton, 52, a former district chief academic officer in Philadelphia, was hired in August. As a self-professed optimist, he had always hoped his high school would avoid gun violence.
Instead, 17-year-old Kareem York, a junior, was in stable condition at Crozer-Chester Medical Center yesterday after surgery for bullet wounds to his legs.
The violent act, at 9 a.m., was just one on the school's long list in recent years.
In November, a Chester High pupil was arrested after firing a gun into a crowd of students, grazing a 14-year-old girl on the chin. A month before that, 25 students were arrested for fighting.
Parents have long complained of crowded classrooms, not enough desks, students roaming the halls, and a shortage of teachers.
The district ranks as one of Pennsylvania's poorest, with low test scores and high dropout rates, and has been under one form of state control or another since the 1990s. In March, Democratic Gov. Rendell appointed a new school board, after years of trying to wrest control from Republican appointees.
This year, the state gave the 4,250-student district an extra $9.4 million to hire new teachers, buy books and supplies, and pay for additional security guards.
Thornton had more ideas.
He worked on getting better bathrooms, better lighting, a senior lounge and other amenities to "enhance student life." At the same time, he increased staff training.
His goal is to "reinvent high school" in a community where the traditional model has not fit. To handle the school's long-standing discipline problems, Thornton said, he wants to have students who cause disruptions placed in alternative programs.
Now Thornton is planning meetings with the city, community leaders, churches and parents to take on the issues that he said had been driving the problems at the schools.
Thornton said some long-standing issues extended beyond the school and into the home and city. He said an involved community was needed to change the school. "You have a school that is trying to re-create itself with new programs and initiatives," Thornton said. "And you have a community that is not moving at [the same] rate."
Yesterday's shooting was sparked by a disagreement between rival neighborhood groups, authorities said. While the police stop short of calling them gangs, Thornton doesn't.
"Call it what you want. To me it's a gang," he said. "It will not be tolerated."
He said some of the groups had been "warring" for years.
According to police, a fight began on the fifth floor between two neighborhood groups, then moved to the fourth floor before ending.
York allegedly had been involved in the fight and was trying to leave the school though an exit on Ninth Street when, authorities said, he was shot by 16-year-old Thomas Gilbert, who was already outside. York ran from his attacker and collapsed several blocks away at West Ninth and Sproul Streets.
School officials would not provide York's name because he is a minor, but a relative identified him as the victim, and other officials later confirmed he was the victim.
York's cousin Talia Spence, 20, showed up at the school in SpongeBob SquarePants pajamas and pink-and-white flip-flops.
He is "a good student," she said. "He don't bother nobody, and he is not no gang member."
"He's a junior . . . who gets A's," she said, "He's not a bad child. We are around that boy 24/7, and he is a full-time student."
A warrant was issued for the arrest of Gilbert, who is being charged as an adult with attempted homicide, aggravated assault, firearms charges and related offenses.
Many students said they hadn't seen the shooting and wouldn't talk even if they had. Some students left campus without permission after the shooting and were seen wandering around the city.
After the shooting, a parade of upset parents arrived in cars and by foot to pick up their children.
"This is just a disgrace. Kids can't even go to school safe," said John Pyatt, 41, who was there to meet his freshman son. "They need to do something with this," he added, saying he was thinking of finding another school for his son.
Senior DeShawn Elliott, 17, who sat waiting for a parent to pick him up, said he hoped the school would return to normal quickly. "We were supposed to take our senior portraits today."
Late yesterday, Thornton was meeting with his school principals.
He does not want yesterday's shooting to define the school. He wants to move forward.
"We had an incident, and we'll deal with it," he said. Thornton said that one positive to come out of the day was the staff's coming together and working on the issues, but that more work was needed. "We have to refocus, dig deeper and harder."
Contact staff writer Mari A. Schaefer at 610-892-9149 or firstname.lastname@example.org.