See also: Agnes (disambiguation page)
Hannah was born prior to the rise of Gilead, and was separated from her parents after the regime came to power. In later episodes we learn that Hannah lives an hour away from her mother's place of assignment, and her foster parents are Commander and Mrs. MacKenzie . She's later revealed to be renamed Agnes MacKenzie.
Unlike in the novel (where she is Caucasian and described as having brown hair), she is of mixed ethnicity, her mother being Caucasian whilst her father is African American.
In expectation of their daughter’s birth, Luke drives June to the hospital amidst crowds of people protesting the recent sharp decline in birth-rates. She is greatly relieved to learn that Hannah is a healthy baby. Shortly after her birth, June wakes up to find Hannah is gone. She initially assumes she’s been taken for a blood test, until sirens begin blaring throughout the hospital. Luke urges June to stay where she is whilst he goes to investigate. June follows Luke regardless and is horrified at the sight of one of the nurses lying on the ground in a puddle of blood, either dead or unconscious. June then runs into a woman holding Hannah. She insists Hannah is her child – it’s implied her own baby died, causing her to have a psychological breakdown. June watches in horror, futilely attempting to explain that Hannah is her baby. Luke arrives, but this prompts the woman to try to flee with Hannah. Fortunately, the police and Luke intervene, returning Hannah to June while the woman is arrested.
June asks Luke to sign a form so that she can pick up her birth control prescription. As she's leaving, she suggests that she doesn't pick it up and surprisingly, Luke agrees. They kiss before June leaves to take Hannah to school.
June is called away from work to go pick up Hannah, who was running a fever, from the hospital. There she is asked a bunch of questions about her capacity as a parent. June then takes Hannah home from the hospital. Luke is waiting for them and they learn that there was an act of terrorism on the Capitol. There was also an explosion at the White House, and martial law was declared. 
After the takeover
June, Luke and Hannah try to escape to Canada and hide in the trunk of their car, a white Volvo 240 sedan, while a man called Mr. Whitford drives them to a secluded cabin near the border. He tells them he still needs to grab them Canadian passports, because U.S. passports "don't mean shit no more". Before he leaves, Whitford teaches Luke how to shoot a gun, which he is clearly uneasy about.
After learning that Whitford has been killed, they try to reach the Canadian border on their own, but their car is spotted by a patrol of black GMC Yukon XL squad cars. They crash at the side of the road, and Luke tells June to take Hannah and run from the Guardians pursuing them . June runs through the woods with Hannah, pausing when she hears gunshots. She tries to hide with Hannah behind a rock, but they are eventually caught. Hannah is ripped away from June, who tries to struggle free, only to be knocked unconscious.
In the present
Serena Joy takes June (known by her patronymic Offred) on a surprise trip, several hours away. Serena meets with Hannah, to show Offred that if she harms herself or the baby then Hannah will be in danger. Offred screams in misery and calls Serena an evil monster. Offred then runs to Commander Fred Waterford to ask him to protect her daughter.
Commander Waterford tells June that he has planned a surprise for her. He puts her in the black Mercedes G-Klasse and instructs Nick to bring her back in three hours. They arrive at a currently abandoned mansion, where Hannah is waiting inside with a guard and a Martha. June rushes towards her but Hannah gets scared and hides behind the Martha. June asks if she remembers her and Hannah nods with the Martha telling June that Hannah's name has been changed to Agnes. Hannah asks if it hurt when they hit her on the head and if she tried to find her. June says yes but Hannah asks why she didn't try harder. Hannah tells her that it's okay because she has new parents now. Hannah notices that June's pregnant and tells her that she doesn't get to keep it. The guard says that it's time to go so June tells Hannah that she'll always love her and that she should enjoy her life. The guard separates them but Hannah runs back to June. June tells her that she has to go and that she loves her. Hannah leaves leaving June kneeling in the snow as she cries.
June has been left behind in the abandoned mansion where she discovers an office. Behind the desk is a photo of Hannah and her placement mother with a caught fish, and on the desk there is a picture drawn by a child, presumably Hannah. It is of the house, a dark child in the middle, a woman in green on the right, and a small Handmaid on the left, which may be her real mother, June.
After June is captured after helping 86 children escape, Hannah is brought to a maximum security prison and held in a glass cage, and has only a doll to play with. She initially seems calm with the Guardians and Aunts. However, having been separated from June for too long in Gilead's indoctrinative system, Hannah no longer recognizes June and runs to the corner of the cage when she approaches. Seeing her daughter brainwashed into fearing her more than Gilead crushes June, and she reveals the location of her fellow Handmaids.
Nick meets with June in a neutral location on Canadian soil with information about Hannah, giving her a file with what he had found out. He discloses to June that Hannah has been relocated to Colorado Springs and enrolled in a domestic arts school where she is a good student.