During the Vietnam War, Trang's backstory is unknown but she was married to Le Nguyen during his service in the Vietnam War on the South Vietnam side. After the Vietnam War with North Vietnam's victory, she, Le Nguyen and the rest of her family was sent to an reeducation camp. After Le was released, she and her family escaped on a small boat and spent many weeks dodging Cambodian Pirates. When they reached Thailand, they were sent to a refugee camp until they were allowed to go to the United States and then they moved to Galveston, Texas, where Le saved enough money to buy a Shrimp Boat, but the KKK burned down the boat. After this, she and the family moved to Medford, East Texas with his family again and opened their own Convenience Store - Medford Mart, which she currently works at with her husband.
Trang seems to have quite a poor relationship with her family. In her first appearance, she and Le apparently have some issues because when he asks her talk to Sheldon's mom and she says she's busy with customers, he says he asks her for so little and he gives her so little.
Trang and Tam seems to have a distant and abusive relationship, as Trang sends Tam lunch letters everyday but the messages always seem to be informing than loving, when Tam said to Sheldon " 'Mom'. Not even 'Love Mom?" In "A Swedish Science Thing and the Equation for Toast, Tam says his mother never lets him have cereal with sugar in it or anything that makes him happy.
Nothing is known about her relationship with his daughters, but it's assumed that they have a troubled relationship with her too, since in the episode "A Loaf of Bread and a Grand Old Flag", Tam was talking about him and his sisters taking their parents to court and bringing them to their knees.