The Care Quality Commission, Her Majesty's Inspectorate of Prisons and Ofsted awarded Rainsbrook STC in Warwickshire improved judgments in four inspection areas, with senior leadership praised for implementing an "ambitious and progressive model of care".
An inspection report published in August 2017 described how violent incidents at the centre had more than doubled over the previous year, with nearly 500 violent incidents involving staff and young people in the six months leading up to the inspection in June.
The findings led the Howard League for Penal Reform to call for Rainsbrook, which is run by MTCnovo and provides accommodation for up to 76 male and female young people aged 12 to 18, to be closed.
However, the latest inspection report following a visit on 2 October 2018 highlighted the positive role the STC's director had played in improving the centre, by hiring a deputy director and establishing a new permanent senior leadership team.
The report said: "Performance information is comprehensive, incisive and accessible, providing an informed overview of trends and patterns across a range of operational areas.
"This has helped leaders develop a clearer understanding of challenges and difficulties."
The report also praises senior management for "rigorously addressing poor and inappropriate practice" and for taking a "thoughtful and intelligent approach" to improving the recruitment and retention of frontline officers.
However, violence remains a problem at the centre with half of young people reporting they experienced verbal abuse, physical assaults, threats and intimidation from peers.
The report particularly noted unacceptable levels of "play fighting" - a matter on which it said staff needed to take more action.
"Staff and young people do not always see the close link between this behaviour and the possible escalation towards actual bullying or intimidation," the report stated.
"While it is positive that trends and ‘hotspots' are quickly identified and understood, a coherent strategy to achieve sustainable reductions in the level of incidents, violence, restraints and use of force remains outstanding."
However, more than two thirds of young people said they felt safe at the centre.
The centre was rated "requires improvement" for overall effectiveness.
In July, the three inspectorates proposed changes to the way they responded to STCs that received inadequate judgments, including more frequent monitoring visits.