Kim Hobson, a finance worker at Sheffield City Council, started volunteering at the city's branch of the Children's International Summer Villages (CISV) in 2007, later becoming their treasurer and chair person.
Despite taking part in numerous fundraising activities for the charity, which educates and inspires children to act for a more peaceful way, Hobson, 54, deceived her colleagues to steal the total of £12,936.05 between March 2014 and February 2020.
Prosecuting Kate Riekstina said: "Her role gave her control of the charity's finances.
"The charity received cash from various fundraisers which would be cashed into the charity's bank account by the defendant.
"On occasions she used some of the money to pay for taxi's to events which was authorised by the charity, but the remainder of the money was kept by the defendant and not deposited. This totalled £10,236.05.
"She also deposited a £1,552 cheque into her own bank account and had a number of cheques countersigned by someone else which she paid into her own account. The total amount she stole was £12,936.05."
A victim impact statement was read out at Sheffield Crown Court on Tuesday from a fellow volunteer of the charity, who had chosen to donate money raised at her own son's funeral to the charity, which Hobson also cashed herself.
"She has gone behind our backs in such an underhand, two-faced way and I feel my judgement of people is flawed.
"Our board director Trevor would have been terminally ill during this time. She then later used cheques with his signature on even though he had passed away.
"I lost my 20-year-old son who took his own life in 2019. I asked for a donation in his memory to be donated to the charity. I asked her to credit the charity account with the money and she made a cash withdrawal for herself.
"I will never be able to forgive her. The happy memories we have made have been tarnished by this."
Hobson's crimes came to light when she told her brother what she had done. He in turn alerted the charity.
She pleaded guilty to theft at an earlier court hearing.
In mitigation, Rebecca Tanner said Hobson, who has no previous convictions, was "genuinely remorseful" and had been "crippled with the guilt and shame" for a number of years.
Ms Tanner said: "She spent years devoting to the charity she has ended up letting down.
Recorder David Kelly sentenced Hobson, of Moor View Road, Sheffield, to 10 months in prison, suspended for 18 months.
He said: "Pride stopped you from taking the obvious steps. They would have been to downsize instead of trying to maintain living in your matrimonial home or to turn to your brother for help, which is what you did when your conscious got the better of you. It's a pity you didn't do that at the outset."
The judge added: "As a result, the people you worked with feel a very bitter betrayal of what you did."
Hobson was also ordered to complete 150 hours of unpaid work.
Following Hobson's sentencing, Beth Turton, current chair for CISV Sheffield, said: "On behalf of CISV Sheffield, I welcome the outcome of the court case and the sentencing today. We feel we have been deceived and financially abused by someone who we had worked with and trusted for many years.
"Our hope now is to reclaim the monies lost, which includes monies raised from the dedicated fundraising efforts of our volunteers.
"We would like to reassure our members and volunteers that we have taken immediate and significant steps to ensure the security of the organisation's funds now and for the future.
"We look forward to putting this distressing incident behind us and moving on with CISV’s plans for this summer and beyond."