Her two dogs, believed to be a pit bull and a Chihuahua, also died.
Marchese and her husband lived in a cottage, a two-room unit rented as an efficiency apartment, after the front of the complex at 526 U.S. 90 was demolished for a pending condominium project.
Her death has been ruled accidental, the coroner said.
Marchese's husband was at work when the fire started shortly before 9 a.m.
Fifteen firefighters and five units responded to the call, along with police. Firefighters found Marchese in the living room.
"The fire had pretty much burned itself out when we got there," said Mike Brown, a Fire Department investigator.
The fire remains under investigation. A state fire marshal joined the investigation, standard procedure in a fire resulting in death.
Marchese is the third person in Harrison County to die in a residential fire since January and the third to die in a fire in Long Beach since 2001.
A woman died in a mobile home fire on Seventh Street near the Gulfport city limits in 2004. In 2001, an 8-year-old girl died in a fire at Gulf Water Apartments on Cheri Lane.
