She is David's great-aunt on his father's side, and has an unfavourable view of men and boys, having been ill-used and abandoned by a worthless husband earlier in life. She appears in the novel's first chapter, where she demonstrates her uncommon personality and her dislike of boys when she storms out of the house after hearing that David's mother has had a son, rather than the daughter to whom Trotwood intended to be the godmother.
Betsey Trotwood plays a bigger role in David Copperfield's later life by taking him in after he has run away from labelling wine bottles in the factory in Blackheath where his stepfather, Edward Murdstone, had placed him to work after the death of David's mother. She provides him with a place at a good school in Canterbury and opportunities for a career in Doctors' Commons, thus showing her complex character.
The character is based on Miss Mary Pearson Strong who lived at Broadstairs, Kent and who died on 14 January 1855; she is buried in the St. Peter's-in-Thanet churchyard. Her sister Ann married Stephen Nuckell, who was a prominent bookseller in Broadstairs from around 1796 to 1822. Mary Pearson Strong's former home now hosts Broadstairs' Dickens House Museum.
There is a public house in Clerkenwell, Central London called The Betsey Trotwood. It adopted the name in 1983, having previously been The Butcher's Arms.