Community Medical Centers provided video to show how the money will help secure a second CT machine for the emergency department in downtown Fresno and build the space for it.
Hospital officials say about 75% of patients who need a CT scan are in the ER, and the new machine will address a critical need.
The donor chose to remain anonymous but shared a message through the medical center.
"Our donor wanted to make sure that we knew, and they knew that they gave back because of the outstanding care that our clinicians gave to them and give every single day. They can, and they do make a difference," said Katie Zenovich, chief fund development officer and senior vice president of development and external affairs.
Some of the money will also be used in pediatrics to upgrade nine rooms and a playroom while creating a new nutrition space.
Hospital officials say the goal is to provide a more comfortable and kid-friendly environment for young patients.