April Moylan, 39, was charged with possession of a firearm by a convicted felon and ordered held Wednesday on $75,000 bond, according to the St. Lucie County Sheriff's Office.
Prosecutors were not immediately seeking additional charges.
"The state attorney's office continues to review the facts of the case, and that review is ongoing," Sheriff Ken Mascara said Wednesday. "That means it is possible there could be additional charges in the future."
It was not immediately clear if she had an attorney.
Michael Eugene Moylan, 45, initially told authorities he awoke early Tuesday morning with a severe headache. The couple went to a hospital where a bullet was discovered in the man's head.
Investigators initially thought Moylan had been hit by a stray bullet, but later realized the couple's story did not match up, Mascara said.
The couple finally told authorities that April Moylan sleeps with a loaded .32-caliber revolver under her pillow. They said that when the burglar alarm sounded at about 4 a.m. Tuesday, she grabbed the gun and it accidentally discharged, shooting her husband in the head just behind his ear.
Mascara said the couple told authorities they couldn't simply call 911 because both are convicted felons and are not allowed to own a gun so they concocted the headache story.
April Moylan previously had been convicted of sale and delivery of cocaine in Palm Beach County, Mascara said. Her husband's criminal record was not immediately available.
He was recovering Wednesday at a hospital. His wound was not considered life-threatening, the sheriff's office said.