In his role as general manager, the 47-year-old was responsible for the safe which also included the centre’s petty cash.
Sentencing Williams in the South Australian District Court on Thursday, Judge Jo-Anne Deuter said he was caught after a trap was set with cash placed in a tin under his desk.
The cash was found to be missing the next day and after Williams failed to turn up for work, police were called.
Judge Deuter said investigations found Williams had used the money to help fund his gambling addiction, which included funnelling more than $1 million into poker machines last year.
He had turned to gambling as a way to pay off debts from a failed business.
“Unfortunately, for what happened later, you had an early significant win,” the judge said.
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“This led to you believing that the only way to recover your financial situation was to continue to win monies by gambling.
“You were gambling, as I have already said, very large amounts of money, chasing that win which would solve your financial problems.
“The money in the remand centre safe provided you with a means to do so.”
Judge Deuter said Williams’ offending involved a significant breach of trust and was too serious for a bond or home detention.
She jailed him for almost three years with a non-parole period of 19 months.
Both were backdated to July last year.