Mary met her future husband, Winslow Schott Sr., at a toy shop she worked at and became his apprentice for a while before they became a committed couple. During that time, they moved to Ivy Town, where they both attended Ivy University. Mary and Winslow soon got married had a son, Winn Jr., and moved to Newark, New Jersey.
Gradually, Winslow became an abusive sociopath but retained a normal facade in front of their son. Mary lived in fear of her husband and did her best to shield Winn from his brutalities. When Winn was nine years old, Mary tried to escape with him to a domestic abuse shelter under the pretense they were going to Disneyland. However, Winslow ran their car off the road, giving Winn a concussion, and threatened Mary that he would hurt Winn if she tried to take their son away from him again. When Winn recovered, Mary lied that they had to turn around due to car trouble. Two years later when Winslow was arrested for a mail bomb, Mary was forced to abandon Winn, knowing her husband, even behind bars, could hurt their son if she stayed. Winn was subsequently put into the foster system.
After Winslow's death
Mary didn't see her son Winn again until 20 years later, after Winslow's death. She revealed to him more parts of his childhood that he had repressed about his father after seeing that Mary was genuine. Winn allowed himself to reconnect with her.
Mary is good at covering up her emotional scars as she hid Winslow's abusive nature from Winn before his arrest. She is a flight type seeing as she left her son in the foster care system, reasoning that she was protecting him from certain death by staying with her. Just like Winn, she covers up the pain of her past with a sense of humor and smiles implying he got that from her before their forced separation.
During the funeral, after the casket exploded, she exclaims "That bastard always wanted to go out with a bang" and laughs as everyone else looks at her.
- Bookkeeping: When Mary was employed she uses these skills to keep her place of work operating.
- Expert engineer: Due to her husband teaching her on how toys and machines operate, Mary gained insight on how things worked both mechanically and inside Winslow Schott Sr.'s mind.
Behind the scenes
- She shares her first name with other notable Metcalf's character Mary Cooper from The Big Bang Theory which has been referenced across Arrowverse, notably on Earth-1.