Zoe Caulfield, 35, of Balk Lane in Birdwell, appeared at Sheffield Crown Court for sentencing after pleading guilty to charges of theft.
Back in 2012, Caulfield became a deputy with the Office of Public Guardian to manage to finances of a known elderly man.
The Office of Public Guardian contacted South Yorkshire Police after she attempted to make a fraudulent claim against her victim - leading to an investigation being launched.
Caulfield tried to withdraw £10,000 and attempted to justify it by saying the victim had owed her the money for presents he had requested she buy for family members.
An investigation into the matter found Caulfield covered up a number of transactions between 2014 and 2017, paying thousands of pounds into her own bank.
Over the three-year period it was confirmed she stole more than £31,000 from her victim.
Investigating officer Lynn Robins said: “This is a sad case of greed and deceit, Caulfield exploited and defrauded her victim for her own means.
“The victim’s illness meant they were never aware of Caulfield’s shocking actions, and sadly, he died before Caulfield appeared in court.
“Through multi-agency working, South Yorkshire Police will continue to investigate these type of crimes against vulnerable adults, ensuring that people who are handling others finances, do so in a way that is responsible and accountable.”
She has been sentenced to 19 months in prison - suspended for two years - 25 days rehabilitation and a four-month curfew.