Reginald Brown was arrested Tuesday in connection to the Feb. 28 blaze in the 8600 block of South Hermitage Avenue, Chicago police announced Wednesday.
Brown, of Gresham, was expected to appear in court Wednesday.
The victims were 10-year-old Porche Stinson Ford and her mother Ieashia Ford, 34, according to the Cook County medical examiner’s office.
Their deaths were classified as homicides "due to house fire due to arson," the medical examiner’s office said.
They were found in a burning house by firefighters about 4 a.m., Chicago fire officials said.
The pair were taken to Little Company of Mary Hospital, where they were pronounced dead, officials said. The fire also injured four other adults, police said.