The incident was reported on Friday just before 8 p.m. on Interstate 84.
Twenty-two students and a tennis coach were on board the bus owned by the Warwick Central School District when it crashed into a tree after the driver became unconscious and stopped breathing.
Students administered CPR before first responders arrived to the scene and took over.
Officials later said Schmidt suffered the medical episode and became slumped over the steering wheel as she accelerated up a ramp to merge into westbound lanes of the interstate.
Police announced later Monday that the driver, 53-year-old Denise Schmidt, died on Sunday.
* More Northern Suburbs news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube