Betsy Baker was born in Brighton, United Kingdom on 20 August 1842. She was the daughter of Martha Russell (1806–1881). She married Tyler Curtis Baker (1833–1921) in 1866 and had five children with him, of which three survived her. One of them, Florence (1872–1968), lived to be 95 years old. Baker died in Tecumseh, Nebraska, USA on 24 October 1955 at the age of 113 years 65 days.
Mrs. Baker was the first person recognized as World’s Oldest Person by Guinness World Records. At the time of her death, she was the oldest verified living person in the world and also the second-oldest person ever. She was also, after Delina Filkins, the second validated person in history to reach the age of 113. Upon her death, Jennie Howell became the world’s oldest person. Her record of being the second-oldest person ever was surpassed by Mary Kelly in 1964.