Mattie was born to wealthy, but emotionally distant parents. Growing up in New York City, Mattie was primarily raised by the housekeeping staff and a mutual resentment grew between Mattie and her parents.^[1]

One night, Mattie was boarding a train at Grand Central Station when she encountered Cassie Webb, who tried to save her and Anya Corazón and Julia Cornwall from Ezekiel Sims. Teaming up, the quartet was able to defeat Sims together.^[1]

• Mattie Franklin was portrayed by Celeste O'Connor in Madame Web.