The Care Quality Commission ordered Yorkshire Ambulance Service to urgently improve its emergency responses after it consistently missed a target to reach 75 per cent of casualties with life-threatening illnesses or injuries within eight minutes.
Target times have shown a major improvement, with the service said to be the best performing in the country following millions of pounds of investment in hundreds of new staff.
The commission said it will continue to monitor response times to ensure standards are maintained by the service.
The service was one of 22 NHS trusts judged as failing to meet quality and safety standards when a new licensing system began in April.
Since then, paramedics have responded to 76.6 per cent of 999 calls within eight minutes under a framework described by local health chiefs as "for the first time suitably ambitious".
Among key changes are a new rota system to ensure staffing levels are matched to the expected demand for services at any time and work carried out with local hospitals to reduce the time it takes to hand over patients to A&E staff. Efforts are also being made to reduce demand from frequent callers.
Jo Dent, regional director of the Care Quality Commission, said: "When we imposed the condition in April we did so against a backdrop of historical failure.
"I know that an enormous amount of work has gone into meeting the target and the fact that collaborative working with other health bodies in the area has borne such impressive results will be a source of great satisfaction and pride for the ambulance service in Yorkshire."
Simon Worthington, acting chief executive at Yorkshire Ambulance Service, said: "Patients remain our highest priority and we would like to reassure members of the public that we are committed to sustaining this level of performance and continuing to provide a high quality ambulance service in Yorkshire," he said.
"Every second counts when someone is seriously ill or injured and we will work closely with our healthcare partners to help make further improvements to our response times for the benefit of patients."