The shooting happened at the Country Villa Seal Beach Healthcare Center on the 2300 block of Beverly Manor Road.
Officers responding to a 911 call just after noon found Laird dead in her bed from an apparent single gunshot wound to her head.
"My daughter works in there and all they heard was the gunshot," said Kathy Terry, the mother of a nurse. "The rest of the staff, administration, was very diligent in getting the staff under control and behind closed doors."
The man, Roy Charles Laird, was arrested in the room of the shooting, police said. He did not resist as he was taken into custody.
Authorities recovered a revolver at the scene.
Investigators are still trying to determine the cause of the shooting.
No one else was harmed, police said.