Hannah had been an average-sized child born of average-sized people, but she began gaining weight at the age of 12. By 24, she weighed 714 pounds and was quite possibly the fattest woman in the world in the latter half of the 19th century. She stood over 6 feet tall and measured three feet across the shoulders. Her size was very likely due to a hormonal imbalance, as she ate only a normal amount. She never drank alcohol; her favorite drink was milk diluted half-and-half with water. "Her temperament was usually as blithe and vivacious as a school-girl's, and she had a rugged good nature that made her very well-liked by circus people," noted her obituary in 1889. Hannah loved to knit, crochet, and sew, and frequently mended the tents and banners for the circus.
Once, she had to be lifted in and out of the window of Pat Harris' Museum in Pittsburgh with a derrick because the building had no door wide enough to accommodate her. She ended up working at the museum for ten weeks, since her grand entrance proved to be such a profitable draw. When touring with the circus, she required her own train car with a double-wide bed, and any hotel where she slept had to reinforce her bed with steel struts.
Hannah and John were, by all accounts, an extremely devoted couple. Hannah was extraordinarily strong and would cradle John in her arms like a baby when he was ill, and once she carried home out of a burning museum. The two had a daughter, Rachel, in 1859. Rachel was "a blonde, with Grecian features and a fine figure, neither fat nor thin, but holds to the beautiful middle degree." She married a police officer.
John suffered a severe fall from a wagon and sustained permanent damage to his spine in 1873. Confined to a wheelchair for the rest of his life, he stopped touring, although Hannah remained in showbusiness. She would not, however, go on tour for more than six months out of the year, as she could not stand to be away from her husband any longer. John eventually weighed over 100 pounds and complained of being "too fat". In his retirement he ran a blacksmith shop with his nephew and sold horse medicine in Frankford, Philadelphia. The Battersbys' Frankford home was furnished with custom-made sofas, chairs and bed with special reinforcements to support Hannah's weight.
In 1889, during a performance at Fall River, Massachusetts, Hannah tripped and fell while climbing down from the stage. She injured her leg and had to ride home in a baggage car. While bedridden from the injury, she developed erysipelas, a streptococcal skin infection. She died at home in June of 1889 and was laid to rest in a 7-foot-wide casket. After her death, a heartbroken John fiercely guarded their home from gawkers who came to see her enormous body.